Once you are you, you will always be you. So you only need the same initial conditions that were present when you were born, once that seed (that makes you exist as you) is there then you will exist no matter how you develop. I don't think that those initial conditions have much to do with the body though, you could be any body since, as you say, there is no identity in nothing, all is the same. I have no idea from a purely scientific perspective what caused nothing to differentiate into different existences, nor what was the process that choose who got to be who.
There is no future when you don't exist, there is no past either, so your question if there are added restrictions to our own future possibility is meaningless. For you, the world is reset to the state where nothing existed, so time doesn't go on for you when you die, there is no universe when you don't exist (not for you) so there are no possibilities to unfould. Neither was there any before you were born if you didn't exist. From purely scientific reasoning it should really be impossible for you to exist at all, or the world for that matter.
When you don't exist then you are the same state that were prior to the universe, that were prior to all existence. Or existence is eternal and who knows what it would be to be outside of it, yet you were...so, where does that leave us? Well, naturally you should exist as yourself as if everything has been reset. If there is a eternal non-existence after you die, then there should have been one before you were born as well, but there wasn't, we do know that at least.
My idea has a flaw though, it calls for individual non-existence, just as we have individual existence. It doesn't seem possible. Yet we do exist as individuals although there was no individual to exist as. Is it a game of chance? Then what is throwing the dice? Could there be some kind of process that actually makes what we call "nothing" a potential something, that is ruled by some kind of law?