Seems like a great group! If you need motivation for them to fight the bad guys you could always throw in some prophecy about how "the saviors of the world will receive the ultimate reward" and then just figure out what that looks like when the time comes. Please keep crossposting! Always love to read about other group's adventures.
I think it's a very real possiblility the demon characters player might, down the line, decide their guy is rejoining the bad guys. I don't think I will be hard pressed to motivate the rest, it just would have been more easy/obvious with a pious char I think. Their group patron will be more of a challenge, but I am sure I will manage :) the game makes them tell me what they want to do a lot, so it's not hard to figure out
It obviously helps tremendously that the players are very motivated and excited to play :)