In a highly unofficial meeting of the AI Reading Group (most of the participants happened to be in a room and we started talking about AI; there was no formal meeting time, no reading homework, and no dessert), we meandered around to discussing rescue simulations and the related idea of reconstructing people based on their digital (or physical) footprint plus memories of their friends and family.
We had wildly differing intuitions about reconstructive personhood. Scott thinks it should work fine to just use third party reports and your Livejournal, and that performing an appropriately superintelligent process on this data should get close enough that he doesn't expect to have a problem with results (and thinks that "close enough" is a meaningful concept, in the same way that today!Scott is very similar to yesterday!Scott). He's inclined to collapse the question of whether or not reconstructed people are "really" whoever they're supposed to be as opposed to more or less similar (a distinction that applies just as well intra-lifetime). And he seems to think that humans are made significantly of low-granularity parts like "introversion" and thinks that weird hidden thought processes might turn out to drop out of all the other constraints on the problem, the same way an alien engineer trying to build a car based on watching videos might put an internal combustion engine under the hood even if none of the videos popped the hood.
Kelsey thinks the connectome has got to be enough to work with - it might get "you during a weird dream" or "you during a wacky drug trip", producing irregular temporary qualia out of poorly chosen electrical impulses and chemicals filling in unknowns about the non-connectome features of your brain, but weird dreams and wacky drug trips are a recoverable state, at least compared to "dead". We might not even need the whole connectome, because we do seem to find people with various brain damage to be "still themselves".
We had differing intuitions about how much people ever actually have overlapping qualia states in their lifetimes. Kelsey thinks the time she got hydrogen peroxide in her eye she was probably having pretty similar experiences to other mindslices in extreme eye pain, but of course when the pain receded she resumed being Kelsey and didn't proceed to be a different person who remembered being subject to unanaesthetized ophthalmic surgery; there were underlying tendencies in her architecture that restored her traits, if not exact state, once the extreme stimulus was gone. And states more interesting than "extreme eye pain" are probably less likely to be shared between people, given their greater number of details.
I think whether or not reconstruction works depends on contingent facts about human mindspace, which a superintelligence can probably figure out (and apply the answer, if the answer is "yes, it works fine") but might be really hard to pin down even that fact with only conventional brains on the question.
It might be that each bit of information about someone, even noisy information, rules out huge swathes of ways a human could be, and that humans can't be so many different ways that this leaves you meaningfully uncertain about which one you're trying to grab. Maybe we're bad random number generators, or good random number generators but proceeding deterministically from a small number of seeds (not like "five", but maybe like "four hundred thousand") with a small range of values each, interacting in ways that are pretty easy to identify and understand with enough processing power and context information about humans in the general case. As a simplified example, someone in my Discord says that in generation 2 of the Pokémon games, whether a Pokémon is shiny or not is possible to derive based on information about its speed stat. One can imagine the same stats of a given monster holding static whether it's shiny or not, but in fact within the constraints of the game some of those values are contradictions. Humans aren't trying to fit onto Nintendo cartridges, but we're trying to fit onto hacky wetware; maybe we contain similar weird connections between seemingly unrelated features of the mind, and nobody is both (*rolls dice*) exactly six feet tall and (*spins wheel*) inclined to use topic-comment sentence patterns more than 15% of the time.
It might also be that humans have enough independently varying parts that small bits of noisy information don't tell you much about other features of the person, and major parts of identity just aren't revealed in typical public records or private recollections however smart the inspecting intelligence is. This seems especially likely to be true of certain kinds of thoughts - memories of dreams that you never discuss, private opinions that you never find a reason to bring up, or even things you did discuss but that only substantially affected your private relationship with someone else who is also dead and can't contribute information to the project of resurrecting you. Are those kinds of things numerous? Are they important? It might depend on the target resurrectee; it might depend on human architecture in general.