An idea is that when the character dies and wakes up as a new incarnation, it's in another body that had died at the same time, but the soul inhabiting the body had no ties to Mr Plot, so the soul was freed/taken by the reaper/ect, and left an empty body, but the body was 'resuscitated' and that's how you wake up in the next incarnation as your soul is taken into the empty vessel. That will at least get us around the whole time skip/random age without explanation problem.