Your piece is quite good, but presupposes carbon to be available. C is basically more abundant that H and O in the universe, the mortar that binds other elements together in molecular structure, and seems to be everywhere Hubble looks. Now, what if a major element required for the recreation of a human subject is absent? The body is destroyed, but another cannot be built...

The idea of multiple yous from various times is a complicated conundrum. The earlier you now has critical knowledge of a future self ... or maybe not? Meeting oneself in a past timeline may be all that is required to set an earlier you upon a different course, a separate timeline, therefore the you that was you continues as though the two of you never met, and in that timeline you had not.

Splitting rails and crossing happentracks.

The rest seems to wander into the metaphysical. I am not a mystic, but as far as I can tell, there is no real way of telling exactly what happens at or after death, other than the distinct absence of life.

Memories. Science is working on ways to store personalities on disks, but not physical memories. Maybe later. Upload and hit save ... or not. One day the choice may be ours.