But no one has claimed that conception created the soul.
was the soul created at the point in time of conception, or prior? I believe the soul is eternal, in that it was created by God, but before the earth was created. Before our birth, we knew God, we dwelled in Heaven, and eagerly accepted the temporary challenge that is mortal life, that we may progress to whatever next stage awaits us.
As intelligent beings, we learn - we seek out ways to learn and grow - to remain forever limited in knowledge is not in our makeup; it is not how God designed us. We are inquisitive by nature, I believe this will be carried with us after death.
Your position is logical, given the soul is eternal. Catholics do not hold that position. We are adopted sons and daughters of God, not begotten as Jesus was. There is only one begotten Son of God. Otherwise, we would be worshipping each other or Mankind in general rather than divinity, which we hold to be only held by the Trinity.
We also believe there already are souls in Heaven. We call them saints. The whole point behind requiring a miracle as proof of sainthood is that it would only be possible if that particular soul is in Heaven and can intervene on our behalf before God. As to Hell, we are specifically directed to not believe any particular soul is in Hell, since we do not know if they repented before death. Even Judas may have been saved, but the odds are not good!
There is an open question as to continued spiritual progress after death. I am not aware that anything canonical has been taught, because there is so little information about what souls do in Heaven other than intervene on our behalf and continually look to God. Since souls only exist in time, we can infer that progress is possible, but not repentence, such as a complete reversal of sentiment.
Dante’s Inferno presents one interpretation of the Catholic understanding of Hell, and includes the Harrowing of Hell performed by Christ. So far as we can determine, it was the old Sheol, a holding place for souls or God’s waiting room prior to the Judgment which held those souls who lived before hearing the message of Christ on Earth. Christ came back with the Redeemed, and those remaining behind were left with the fallen angels.
It is all speculation at this point, since ambiguity is necessary. We are not supposed to be certain, since certainty precludes hope, and the mandate is to hope that all men be saved. There is no mandate to know that all men be saved. Much of the theological conflicts of the Church have involved an inability to deal with the uncertainty.