At the risk of appearing to be self-promoting, I have a tech podcast myself in which we talked about this very thing: Tech Memento Mori
We covered a bunch of these questions and included links to some good resources. Personally, I’ve been filling out Erik Dewey’s The Big Book of Everything and I plan to both store it in 1Password, but also print it out in a 3-ring binder and store in a safe place.
There was also a thread on this topic here in MPU last year that had some good advice as well: Digital Journaling, Digital Up-Keep and the After-Life