souls beings shaped by past lives is one theory. There are theories out there that there is no reincarnation cycle and that your soul now is comprised of a bit of collective unconscious, there are theories that the soul is shaped by you and may be inhuman because of your nature.
I believe that yes, a soul is shaped by its first incarnation, I wouldn't doubt there to be any just hatched dragons that entered the reincarnation cycle. Newborn Dragons are not immune to death, and are quite a bit more fragile than a fully grown dragon.
The maximum effective range of an excuse is zero meters.