For example, brain scans while alive and then something like the Visible Human Project (body sliced into cross sections) coupled with a copy of your genome. This could perhaps also be supplemented by a daily journal. Surely a powerful enough AI would be able to recreate the human that created those writings using the information provided?

Cryonics is an ambulance ride through an earthquake zone to the nearest revival facility, The distance is measured in years rather than miles, and the earthquake is the chances of history. The better the preservation, the lower the technology required to revive you, and the sooner you will reach a facility that can do it.

A "powerful enough" AI isn't magic: it cannot recover information that no longer exists. We currently don't know what must be preserved and what is redundant, beyond just "keep the brain, the rest of the body can probably be discarded, but we'll freeze it as well at extra cost if you want."

On a present-day level, the feted accomplishments of Deep Learning suggest to me that setting such algorithms to munch over a person's highly documented life might be enough to enable a more or less plausible simulation of them after death. Plausible enough at least to be offered as a comfort to the bereaved. A market opportunity! Also, fuel for a debate on whether these simulations are people.