Hello Dionysus,
Was Jesus with the Father before his physical existence?
If this is true then does it not answer your query of those that were born before Jesus?
Why would we think the 'sins' of our heritage was not forgiven with Jesus' mission?
Humanity's challenge is this living school, do you think it would be a loving Father's will?
What would be the state of humanity had Jesus not been placed on the cross, was that the purpose or was the purpose to follow the will of the Father and teach that by example?
Something to think about even if the answers are mute.
Seumas