Catholics believe in the Real Presence of Jesus in the Eucharist, meaning that what appears to be bread and wine is really Jesus’ body and blood—not just a symbol of his body and blood. When Catholics receive Holy Communion, it is an expression of the unity among all those in communion with the Catholic Church throughout the world, who maintain the belief in the Real Eucharistic Presence of Christ. Therefore, only those who believe in the True Presence may participate in this sacrament of oneness with Christ and his Church. “… [T]he celebration of the Eucharistic sacrifice is wholly directed toward the intimate union of the faithful with Christ through communion” (CCC 1382). 
 
Ultimately, Catholics believe that we cannot celebrate this unifying sacrament with other Christians while there are disagreements about the Eucharist itself. However, Catholics pray for the day when we can reconcile with other Christians and share in the unity of God’s people through the Holy Eucharist. 
 
The United States Conference of Catholic Bishops expresses this desire for unity: 
 
“We pray that our common baptism and the action of the Holy Spirit in this Eucharist will draw us closer to one another and begin to dispel the sad divisions which separate us. We pray that these will lessen and finally disappear, in keeping with Christ’s prayer for us ‘that they may all be one’” (John 17:21).

The Catholic doctrine of the Real Presence is the belief that Jesus Christ is literally, not symbolically, present in the Holy Eucharist—body, blood, soul and divinity. Catholics believe in the Real Presence of Christ in the Eucharist because Jesus tells us this is true in the Bible: “I am the bread of life. Your fathers ate the manna in the wilderness, and they died. This is the bread which comes down from heaven, that a man may eat of it and not die. I am the living bread which came down from heaven; if any one eats of this bread, he will live for ever; and the bread which I shall give for the life of the world is my flesh. The Jews then disputed among themselves, saying, ‘How can this man give us his flesh to eat?’ So Jesus said to them, “Truly, truly, I say to you, unless you eat the flesh of the Son of man and drink his blood, you have no life in you; he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is food indeed, and my blood is drink indeed. He who eats my flesh and drinks my blood abides in me, and I in him” (John 6:48-56). Furthermore, the early Church Fathers either imply or directly state that the bread and wine offered in the celebration of the Lord’s Supper is really the body and blood of Jesus Christ. In other words, the doctrine of the Real Presence that Catholics believe today was believed by the earliest Christians 2,000 years ago. 
 
This miracle of God’s physical presence to us at every Mass is the truest testament to Christ’s love for us and His desire for each of us to have a personal relationship with Him. 
 
Thus, if Jesus were only speaking symbolically about eating His flesh and drinking His blood, as the Protestants say, then what He really meant was “whoever persecutes and assaults me will have eternal life” — which, of course, makes nonsense of the passage. 
 
Bread and wine are not normal or natural symbols of flesh and blood. To call a man a “fox” is an understandable symbol for cleverness. To call a man “bread” is not an understandable symbol, without some explanation. Either the symbols would have been clearly explained (which is not the case) or Jesus spoke literally (which is the case).

Trust the Church in this to which Christ gave the power to bind and loose. 
 
In the Passage you reference, Jesus says, “What God has joined together let no one separate.” (Matt 19:6). But not every exchange of marriage vows is ipso facto a work of God. Vows must be properly exchanged by people of requisite maturity etc. The annulment process seeks to investigate if God had in fact joined the couple or not, based on evidence supplied. If not, a person is free to marry, for they were not truly married the first time.

Reading the Bible is of course to be encouraged. The problem is not reading, it is interpreting. If in the past priests once encouraged the faithful to be cautious in reading the Bible, it was only to protect them from the Protestant tendency of private interpretation, which leads to a lot of divisions. That priests ever did discourage the faithful from reading the Bible is exaggerated in terms of its extent and severity. 
 
However, any such warnings ought to be seen in the light of what private interpretation has wrought: namely some 30,000 different denominations of Protestants all claiming biblical authority for their differing views. 
 
Today, Catholics are strongly encouraged to read and pray with their Bible, but to strive an conform their understanding of the text to Church teaching and norms of Catholic Biblical interpretation articulated in the Catechism.

I am unaware that Pope Francis has used this phrase. However, it is a rather common expression today among priests and theologians. It describes the unfortunately common reality of many Catholics in the pews who have received all their Sacraments, and may even faithfully attend Mass each Sunday and go to confession at least once a year, but they have never really met Jesus Christ or encountered his presence powerfully. 
 
Sadly, many Catholics, often due to poor catechesis, reduce the sacraments to rituals, rather than to living and real encounters with the Lord Jesus, who himself is the true celebrant of every Sacrament. The purpose of all the Sacraments is to sanctify us, and in particular ways, to lead us deeper and deeper into a life changing and transformative relationship with Jesus Christ. They are to put us in living, conscious contact with Jesus, so that we see our lives being changed. 
 
But the all-too-common experience of many Catholics is that Sacraments are only vaguely appreciated in this way. Many see them as tedious rituals, rather than transformative realities. Too many seek the shortest Mass almost as if it were more like a flu shot, a kind of “necessary evil,” to be dispensed with as quickly and painlessly as possible. Confession too is avoided. 
 
Very few Catholics come to Mass expecting to be transformed. In a way, people put more faith in Tylenol than the Eucharist since, when they take Tylenol, they expect something to happen, they expect the pain to go away and healing to be induced. But too many Catholics do NOT expect anything like this from the Holy Communion with Jesus. 
 
This is what is meant to be sacramentalized, but unevangelized. It is to be faithful to the pew and to the Sacraments but to lack the evangelical zeal, joy and transformation one would expect from a more fruitful reception of the Sacraments. It is to go through the motions but not really get anywhere. It is to receive Jesus but not really experience him in any meaningful manner. 
 
Pastors, parents and Catechists need to work to overcome what amounts to a lack of deep faith in, and experience of, Jesus. Far from denigrating the Sacraments, the phrase seeks to underscore the truer and fuller reality of the Sacraments, which are not mere rituals, but powerful realities if received fruitfully.

In the ancient Church one usually entered the sanctuary through the baptistery and the custom of blessing oneself with the water naturally took up as a reminder of baptism. In later centuries as church buildings grew larger and doors multiplied, small fonts were placed near those doors and the tradition continued. 
 
The practice of placing sand in the fonts for Lent is a tired aberration and not prescribed by any norms. At no point in the liturgical year is it appropriate to cease remembering our baptism.

While a brief column such as this cannot possibly plumb the depths of the questions you raise, a few observations should be made. 
 
First, it does not pertain to God to annihilate any rational creature he has made. Thus, angels and men have an immortality that pertains to their souls; and for humans, one day, to our bodies as well. Having given the gift of life, God never withdraws his gift. While it is true that demons, and the human souls in hell have definitively rejected his love, God does not thereby cancel the love he has extended to them. He continues to sustain the life even of his enemies, though they choose to live apart from him and what he values. 
 
Secondly, your question tends to put God within serial time, where time passes incrementally from future to present to past. And, thus, the question occurs to us, "Why would God at some time in the past, knowing what a person would do in the future, bring them into existence today?” But God does not live in or relate to time in this manner. For God, past, present and future are all equally present. And thus, while God's inner life is mysterious, it is clear to us that God does not deliberate in the manner we do. Time does not unfold for God like it does for us. So, to some degree, even the way we phrase our questions is invalid. God does not ponder “A”, look forward to “B”, and then do “C”. 
 
But let us for a moment assume God did act temporally in this way, and that at some point in the past, God, knowing that a person would do horrible things in the future, considers their existence today. Let us say, that seeing the bad things they would do, he simply vetoes their existence. 
 
But what does this do then to human freedom? In effect, it cancels it. Why? Because if in knowing that a person will choose badly, God preemptively vetoes their existence, then the whole process of choosing God and his kingdom values is “front‐loaded” and none of us who do exist are really free. Freedom would only be theoretical since no existing person actually can or ever did say “no.” If we are not free to say no, we are not really free to say yes to God and love Him. 
 
Many more things related to the questions you raise could be said. But for now, let it be enough for us to say that the answers are caught up in the mysteries of God's love, time, and human freedom.

The practice of mixing water and wine was common in the ancient world. Wines were usually heavier than most modern vintages, and to dilute them a bit made them more palatable and less inebriating. People also drank more wine since water in the ancient world could not be purified easily as is done today. Thus, the wine used at Mass was mixed with water before the consecration in the usual manner of all wine. 
 
Mystically it came to represent our inclusion into Christ's Body by our baptism. The priest says: "By the mystery of the water and wine, may we come to share in the divinity of Christ who humbled himself to share in our humanity". 
 
Though the practical reason to mix water and wine no longer is needed, it still remains a powerful symbol and so its practice remains.

As you rightly point out, fornication (premarital sex) is a very serious sin, which has sadly received widespread acceptance in our culture. The related sin and trend of cohabitation makes matters even worse because of its public nature and capacity to give scandal. Scripture in many places describes the sin of fornication as a mortal sin, declaring that it excludes one from the kingdom of heaven (for example Ephesians 5:5, one Corinthians 6:9, Galatians 5:21, among others). 
 
God consistently condemns fornication because of the harm it does the human person, the sacrament of holy matrimony, and children. Children conceived of fornication are at high risk for abortion since 85 % of abortions are performed on single women. If they survive this risk, they are still likely to be raised in irregular situations that are not best for them. This in turn leads to many other social ills. 
 
Consequently, fornicators not only sin against God's gifts of marriage and sexuality, but also sin against justice by engaging in behaviors that harm society and children. 
 
What then is a priest to do when he prepares couples for marriage who are often cohabiting? Of course there are many prudential factors involved. At least the couple is trying to set things right. Having them seek separate domiciles is best but not always feasible. But surely every priest ought to teach such couples of the seriousness of their sin and insist they live chastely and sleep in separate rooms. While he cannot enforce this, he ought to instill in them a holy reverence for God who sees all things. 
 
In order to avoid scandal that is easily given by cohabiters who cannot separate, many priests make some mention at the wedding of the fact that he instructed the couple to live chastely and was glad that they were willing to give heed to the holy instruction of God. He can be discrete but clear, and even use a little humor. But simply ignoring the issue altogether when a couple has publicly cohabited offends against the common good by giving the impression that such behavior is good or no big deal. Silent pulpits are a sadly common source of scandal.

Since the early days of Christianity, wearing chapel veils has been a common practice among faithful women. Chapel veils, also commonly called mantillas, which comes from the word manta, meaning cape, are typically circular or triangular shaped pieces of black or white lace that are draped over a woman’s head when attending Mass, or in the presence of the Blessed Sacrament. Traditionally, the black veils were worn by married or widowed women, while the white veils were worn by young girls, or unmarried women. 
 
Throughout the centuries, the use of the mantilla by women has had many purposes. The wearing of the mantilla is an act of veiling a woman's physical beauty (as a woman’s hair is traditionally considered her crowning beauty), so that the beauty of God may be glorified instead. It is also a way of emulating Mary, our mother, who is the archetype of purity and humility. Moreover, the mantilla, or chapel veil, signifies the role of women as a life-bearing vessel. Oftentimes, the chalice holding the blood of Christ is veiled until the Preparation of the Gifts, and the tabernacle is veiled between Masses. Both of these vessels hold the Eucharist – the very life of Christ. In a similar fashion, the woman was endowed by God with the special gift of bearing new human life. Because of this, women, as all things holy and sacred, are veiled. 
 
Before the Second Vatican Council, the wearing of chapel veils was required for a woman when attending Mass, as a symbol of her modesty and humility before God. Although this practice is no longer required, it is still very much supported and encouraged by the Church as a sign of reverence and piety while in the presence of God. 
 
In addition to being a long-standing and beautiful piece of our Catholic tradition, there are three great reasons to wear a mantilla: (1) veiling is a physical reminder that you are entering a Sacred space, (2) veiling is a sign of feminine dignity, and (3) veiling is half of a dual-tradition whereby a woman covers her head (by covering her hair with a veil), and a man uncovers his head (by removing his hat) when entering a church as a sign of humility and devotion.