Sunrise,
Missed you!

You haven't mentionned the role our Spiritual Guardians and Helpers play in this. Like Antwhn, I have to believe spirit helps choose whether the heart-n-soul wants/needs longer time on the earth.
If I eat too much salt and fat, or tumble off a ladder, etc for some purpose, I could damage my body for those purposes, but not because I want to leave quite just yet (purely hypothetical.) So then maybe my Helpers make a deal (or already have made a deal) that I can use another body for awhile. That will of course alter my experiencing somewhat, but perhaps those involved are from the same Disk, so we'll get it all sorted out when we get back, if necessary.
Here's to more answers from micro-biology, the Pope, NDEs, wherever!
(Except that I'm beginning to think that each chakra/energycenter controls one layer of body, and the heart controls the emotional body, on which we put alot of emphasis. So transplanting any major organ that aligned with a chakra/energy center would make a big difference in the experiences of the soul, which maybe is a word for the total mix, or is an interpenetrating love-vibration that holds them all together? Gotta work on that one tho.)
As usual, Sunrise, you bring intriguing questions!
bets