If we therefore limit the possible avatars that our simulator God is using on Earth to the major monotheistic religions of Christianity, Islam, and Judaism, and consider them all equiprobable; plus a 25% chance that this God is jumping from one avatar to another, or chose to reveal Himself via Jesus but then Paul screwed everything up, or some other minority position; then p(chr0|ego, ent, sim, Earth) = .25.

I have a big problem with this step. Why should (have lots of adherents) imply (is point of simulation)? Surely there will be more unskilled play-throughs of "simgod" than skilled ones. I think this number can be made arbitrarily low just by adding in all known religions...