Your suggestions are fine except no.2. What if the player that become abandoned empire decides to start playing again?
it's atleast should work against players with 1 province and who have less then 200 points(anyway they cant be attacked)
and such thing will give players new chance to start from begining in another place. i think on realms many ppl abanbone their empires beacuse of very agrassive neighborhoods who dont allow normally evolve.