This level of detail is not supplied to us by the biblical texts. Nor are such details defined in the magisterial teachings of the Church. Hence, we are in the realm of speculative theology when it comes to such matters. 
 
We ought to begin by saying that the Day of Judgment will not be a day like any other. There are many unknown factors, especially related to the mystery of time, that underlie our speculations. For example, is Judgment Day really a day of 24 hours? Or is it a moment in time that happens like a flash? Perhaps it is a longer period of some indeterminate length? Does time even exist, as we know it now, at a moment like that? 
 
There is also a premise in your question, which is not unassailable. Namely, that Purgatory ends on the Day of Judgment. We do not know this. Perhaps Purgatory, or the process of purgation, may exist for a time after the last judgment. But here too is another question. What does it mean to say that something exists “for a time,” if time as we know it no longer exists? 
 
Perhaps the best we can do with a question like this is to say that it is not for us to know such details, and that God will accomplish the purifications and purgation necessary in ways known to Him. 
 
It would certainly seem that such purification would in fact be necessary based on Scripture, which says of heaven, Nothing impure will ever enter it (Rev 21:27). And thus, while Purgatory, or the process of purgation, is set forth in Scripture for us who die now, how God will accomplish this for souls in the rarefied conditions of the Great Second Coming is known to Him, but not revealed to us with enough specificity to answer your question without speculation.

Generally, the norms of the Church indicate that the altar should be fixed, that is, immovable, made of stone, and located in the sanctuary of the Church, that is, in an area of the church distinguished from where the people gather and are seated. (“Built of Living Stones” 54, 57) 

At first glance, it would seem that your pastor is operating outside these norms and that the appropriate place for him to celebrate Mass is at the main altar of the church. 

Sometimes however, in older, or larger churches, the pastoral challenge you described is present. In such cases the use of a smaller altar, closer to the people, (as is done in some larger basilicas), is employed. 

The movable altar should be truly noble, not a simple folding table, and dedicated to no other purpose other than the celebration of the sacred liturgy. While this is not ideal, in some instances it may be pastorally allowable, especially if recourse to a chapel for daily Mass is not possible.

It is perhaps too absolute to say the Church has "an answer" to suffering, and why God permits it. The full answer to this is ultimately mysterious, and has many aspects, which are hidden from our view. 
 
To be sure, we do have elements of an answer, which God reveals to us, or which human reason can supply. One element of an answer is the existence of human freedom. One way God could prevent a lot of suffering would be to cancel human freedom whenever it was abused. But God, it would seem, does not usually see fit to do so, and his respect for our freedom is very consistent. 
 
Another aspect of an answer is that suffering often brings growth and opens new possibilities. Perhaps God sees these fruits and thereby allows some degree of suffering. 
 
But again, these insights are part of an answer. They do not constitute a full or complete answer to the great mystery of suffering and why God allows it. These insights tend to bring up even more questions. Fundamentally we must accept that we do not have an absolute answer to the problem of suffering. 
 
While it is fine that atheists raise this issue, (for it is a valid question we all have), the demand by them for an absolute answer is not reasonable. We must also ask them to consider that not everything has a simple answer. 
 
Thus, if they will demand that I must absolutely answer the question, “Why is there suffering?” then I would also like to ask them to give an absolute answer to the question, “Why is there love? Why is there generosity or a passion for justice or self‐sacrificing heroism?” 
 
If you and I must account for the negative side of suffering, then perhaps too our critics must account for the existence of love. If they are honest they will perhaps admit that while they can give a partial answer, they cannot fully account for these things. 
 
The bottom line is, not everything can be absolutely answered. To unreasonably demand answers from others, when they cannot supply them either, is not itself a rational or adequate reputation of the existence of God.

Major exorcism is a matter of supreme discretion and confidentiality. The identity of the diocesan exorcist is not generally made known, except to those who need to know. 
 
While procedures in dioceses vary a bit, it is most common that the exorcist works with a team that includes at least one other priest, a medical doctor, and a properly trained psychotherapist who all assist in the assessment of whether a person is actually possessed. 
 
If major exorcism is considered advisable, the exorcist proceeds with it, but only with the explicit approval of the bishop, who must concur with the judgment to go ahead with the major exorcism. 
 
Here too, the exorcist should never work alone, but with at least one other assisting priest and an appropriate team. It is almost never the case that exorcism is a “one and you’re done scenario.” Generally exorcisms are conducted over a series of sessions, sometimes weeks or months apart. 
 
If one suspects demonic possession, the first place to begin inquiry is always with the parish priest, or another trusted priest. If that priest has reason to suspect possession (rather than obsession or torment) then he should contact the Diocese and request consultation with the appointed exorcist.

No, if that is what they are doing. The proper responsorial Psalm, from the day should be said or sung, however there are exceptions. Liturgical norms state the following: 
 
[T]he responsorial Psalm, ... should, as a rule, be taken from the Lectionary. It is preferable that the responsorial Psalm be sung … In order, however, that the people may be able to sing the Psalm response more readily… Psalms… chosen for the various seasons of the year… may be used in place of the text corresponding to the reading whenever the Psalm is sung. If the Psalm cannot be sung, then it should be recited…. There may [alternately] be sung either the Responsorial Gradual from the Graduale Romanum, or … Graduale Simplex…or an antiphon and Psalm from another collection … providing that they have been approved by the Conference of Bishops or the Diocesan Bishop. Songs or hymns may not be used in place of the Responsorial Psalm (GIRM # 61) 
 
As can be seen, an exception can be made for reasons stated to using the psalm for the day. In some parishes, the ability of the musicians and or the people to learn and use different responses each week varies a good bit. Thus pastoral provision permits the use of certain seasonal psalms and refrains. But, substituting hymns in place of the responsorial Psalm is not permitted and only texts approved by the Bishops are to be used. 
 
Thus it is possible to see how the words of the psalm that are sung may differ from what is in your prayer book, but only if the variant text is approved by the Bishops. 
 
For musicians, parishes or pastors to make unauthorized changes to the texts of the psalm is strictly prohibited. Most commonly the forbidden changes involve altering the text to be “inclusive.” But theologically, the “Man who walks not in the counsel of the wicked” etc., is often a reference to Christ, and altering the text loses the Messianic reference. Hence bad and unauthorized changes yield bad theology. It is rightly prohibited. 

The Catechism states regarding Homosexual orientation: Its psychological genesis remains largely unexplained (# 2357). Hence the Church has no official doctrine that would either affirm or deny your assertion.
 
The moral requirements for a person of same-sex attraction do not vary based on the origin of the orientation. Rather, “Basing itself on Sacred Scripture, which presents homosexual acts as acts of grave depravity, tradition has always declared that "homosexual acts are intrinsically disordered. They are contrary to the natural law. They close the sexual act to the gift of life. They do not proceed from a genuine affective and sexual complementarity. Under no circumstances can they be approved.” (Catechism # 2357).
 
It is not unlike a diabetic, who may be so for genetic reasons, or by acquiring the condition, (perhaps by overeating). The bottom line is the same; they must carefully regulate their diet. Thus, whatever the origin of homosexuality, the requirement is clear, one must embrace the life of celibacy that God enables.

There are details of the Christmas story in the modern imagination that come to us from sources other than Scripture, details which may or may not be accurate.
 
So, it is true we do not know the exact number of the Magi who came. Many presume the number three, since three gifts are mentioned: gold, frankincense and myrrh. But there may have been two Magi, four or more, we just don't know for sure.
 
Likewise, the modern imagination tends to bring the Magi to the creche the very night of Jesus’ Birth. Yet Scripture implies that their visit took place, likely, at a later time. This is because the text speaks of them finding Mary and the child in a house (Matt 2:11), not at the creche.
 
Thus, liturgically we distinguish the two events and emphasize as well in Epiphany the “manifestation” (which is what “Epiphany” means) of Christ to the Gentiles and the call of the nations to faith and worship of Christ.

Yes, and to add to your reflection, we also seem to move forward and backward in time during the Christmas cycle. The Feast of the Holy Family, celebrated on the Sunday between Christmas and New Years features a Gospel of Jesus at 12 years of age. And then at Epiphany, celebrated more than a week later, Jesus is back to being an infant. Further, we observe the Feast of the Holy Innocents on December 28, a terrible slaughter that took place after the visit of the Magi, and then we move backward in time to celebrate the feast of the Epiphany on the Sunday near January 6.
 
Some of these anomalies are explained by the fact that the liturgical year did not develop evenly over the centuries. The feasts of St. Stephen the Martyr, and St. John the Apostle are very ancient feasts on the Church’s calendar. The celebration of Christmas, and the feasts related to Christmas, developed in later centuries.
 
It surprises many of us moderns that the ancient Church did not focus a great deal on the birth of Christ. We are very sentimental about Christmas and the baby Jesus. But the early church focused primarily on the Paschal mystery of Jesus’ passion death and resurrection.
 
In later centuries the Christmas feast became more elevated. But the focus was still more theological than sentimental. Thus, It did not seem so alarming that the very day after Christmas, we were back to celebrating other saints such as St. Stephen and St. John.
 
Later, as a celebration of Christ's incarnation deepened, theologically and culturally, there was developed the octave of Christmas. But the Church did not feel free simply to move aside the feast of St. Stephen and St. John, which were very ancient.
 
As for the chronological whiplash of moving back and forth in time, within the Christmas feasts, we should recall that in the celebration of the Sacred Liturgy we access eternity, rather than merely chronological time. For God, all times and events are equally present, and we meet him there, rather than simply on our schedule.

The liturgical environment has stricter rules than Catholics are necessarily obliged to follow in their own homes. While it may be ideal that our homes perfectly reflect the liturgical cycle, practically speaking, many Catholics begin decorating earlier in the month of December.
 
As for celebrations on Church grounds, that is a matter of pastoral judgment. Frankly, most pastors are rather relaxed about this, understanding that cultural influences, even if less than ideal, can be respected out of regard for the legitimate wishes of people to celebrate conveniently.
 
You are encouraged to listen carefully to your Pastor’s teachings, and strive to keep Advent as much as possible. But it does seem that some leeway in these matters is acceptable.

The norms of the Roman Missal state that, While the Priest is receiving the Sacrament, the Communion Chant is begun, its purpose being to express the spiritual union of the communicants by means of the unity of their voices, to show gladness of heart, and to bring out more clearly the “communitarian” character of the procession to receive the Eucharist. The singing is prolonged for as long as the Sacrament is being administered to the faithful…. (GIRM # 86). The instructions also state: When the distribution of Communion is over, if appropriate, the Priest and faithful pray quietly for some time. If desired, a Psalm or other canticle of praise or a hymn may also be sung by the whole congregation. (# 88).
 
Note then the emphasis on the “communitarian” nature of this moment. And while private prayer is not wholly excluded, neither is it extolled as the main point or purpose to be pursued at the time of receiving Holy Communion.
 
The Sacred Liturgy is fundamentally a public and corporate act of worship of the whole Body of Christ together. It is not essentially a private devotion. The norms do permit a time after communion for silent prayer, if this seems appropriate. The length of such time and the use of this option will vary depending on the needs of the congregation and other factors.
 
Your concerns are understandable, but they need to be balanced with what the Church teaches us about what the Liturgy most fundamentally is. Consider that in the first Mass, at the Last Supper, the Apostles did not go off and have private conversations with Jesus. Rather, they experienced him corporately, and the Scripture says, that after partaking of the Sacrament, they “sang a hymn” (Mt 26:30). If we extend the first Mass to the foot of the Cross, there too, those that made it that far, stayed together and supported the Lord and each other.
 
Private prayer and Eucharistic devotion are to be encouraged, but, there is a context where this is best. Public prayer is also good and to be encouraged. It too has a context that should be respected for what it is.