Lots of things we differ on here.
Our souls are not chemical. A soul is no form of mass-energy or space-time. That would be Manichean.
Also, that does not mean they are eternal. Catholics differentiate between eternal and forever. Nothing is co-eternal with God. Souls are not eternal; but they are immortal and forever. Eternal means a no-space, no-time condition because no change is possible, and God does not change since any change would be away from perfection. Since God created space and time as well as all the matter in it, only He is eternal, and everything else is forever. Forever is an infinite space, infinite time condition, which applies to us.
Humans are not just souls, but body and soul. The Resurrection will be resurrection of a body also, a perfect spiritual body that does not experience the ills that affect our bodies now because of sin. Sin brought death into the world. Once of the consequences of this doctrine is that Mary, who was conceived without sin, never experienced sickness, and she was assumed into Heaven rather than died. This was what was supposed to happen to Adam and Eve if they never bit the apple. Bodies are not just vessels or suits we walk around with for a time, but will be reconstituted at the Resurrection.
Note that when Jesus said we would “Be like the angels” he was speaking in the context of marriage. There is no need for immortals to conceive children. It did not necessarily mean we would be disembodied souls.
The idea that we would exist as only souls after death without bodies is a little Manichean, and very Gnostic. Catholics reject that.
I have heard something about this story about two plans, but not much because we do not consider it canonical. At the very least we do not hold Satan on the same level as Jesus. Satan is a creature, and Creation was by the Father, through the Son, and with the Holy Spirit. Jesus, as being One with the Father, is eternal and not a creature. He was begotten of the Father from eternity, not created. He came from eternity for a time and returned to eternity without changing. This is part of the mystery that humans cannot wrap their minds around.
The filter idea is a useful metaphor. After death, there is no salvation from Hell once entered. The parable of the sheep and the goats tell us that. I doubt there are many Christians sects that do not believe that.
I agree. I think there is some confusion in that the sentence of Hell and Eternal Damnation is made upon Judgement Day - AFTER our resurrection. Between the "now" and the "then" is a temporary holding place. For the souls who have been good, this place is far more pleasant than earth and (personal bias injected) this is perceived as Paradise, not Heaven. For the souls who have been predatory, who have sought evil their temporary reward is a Spiritual Prison. After all, after the crucifixion didn't Christ go to this Prison and preach to these souls? What would be the point of this exercise if they were damned to hell, anyway? To tease and torment?
I believe that even after death, there is an opportunity for repentance, however once our nature is established the personal motivation for true repentance as a spirit is limited. For example, I doubt that Adolf Hitler, in death is much different than Adolf Hitler was in life. I doubt he has any remorse for the sins he committed in life - BUT if he did, and truly repented and asked forgiveness, must not he be forgiven too?
Can any soul truly enter Heaven, prior to Judgement Day - unless Judgement Day is in a different time/space continuum than us - and is currently happening. For us here on earth, Judgement Day is still coming - arriving after the resurrection of the dead.