Persona's are confirmed. From Streamers who played with a very limited exposure (3 hours) they claim the AI did seem moderately smarter, but with too little time playing it they cannot say for sure.
IIRC nothing has been said or fully confirmed in this area yet. They have not really commented on AI opponents at all, actually. I believe that the map actually *physically* expands in the Modern Era, as in, the land does not exist at all prior to it, therefore meaning anything occupying that land is probably actually generated as the Map is expanded, but this is also not confirmed, I am only deducing it from how Multiplayer will work.