I'm not familiar with the original passage, but the assertion "the bits of knowledge obtainable about even prominent historical personages are far fewer than those describing a human mind" is questionable. If macroscopic decoherence is very reversible then it's false, among other possible counters. Either way "so the resimulations are just approximations" could still be rather misleading considering many commonsense definitions of "approximation". (I do not assume that khafra endorses Stross's observations or that Stross made quite those observations, only that Stross made approximately those observations.)
If macroscopic decoherence is very reversible
That's a very big if. Decoherence is often defined in terms of effective irreversability.
http://www.dailycamera.com/boulder-county-news/ci_18282009?source=most_viewed
I'd imagine the efficacy is halfway between proper cryonics and embalming and burying; the more interesting part may be the festival. Nederland is a small town 20 miles from Boulder, CO. I doubt the festival attendees are cryonics advocates, but they don't seem prone to the negative associations corpsicles often raise. Perhaps it's just because Boulder, Colorado is full of weirdos, but I wonder if there are more exploitable effects in play.