The rules ARE precise! You're just trying to apply them wicked prematurely, with no information to go by. The rules are:
Whatever is part of the character's old life, the character doesn't keep.
Whatever is part of the character's new life, the character gets.
Overriding both, whatever is part of the character's self, the character keeps.
I can't possibly tell you sight unseen whether a character's former potential future (that is, which ungiven future options she's chosen) is part of her old life or part of her self. I wouldn't be able to decide that unless I knew the character. You won't be able to decide it until you know the character either.
For most characters, the possibility that they will one day move on from a second life to a third is probably part of their selves, so they'll get to keep it. But I wouldn't go so far as to call that the rule.
I can tell you that for Julia's character Rose, running The Garden was part of his old life, not part of his self, so he didn't get to keep it. I can tell you that I thought that the maestro d's sex move was part of his old life, not part of his self, but I've been thinking about it and I might change my mind. If I do, he'll have two sex moves, and that's pretty interesting.
-Vincent