Sorry about the late response! Currently putting some additional stuff together before the Screenshot Saturday post.
Banes double elemental damage, yes. Resistances will definitely be nice to have against Aeternator, as he's got plenty of elemental damage. Be careful, though, because he's also got plenty of non-elemental attacks that'll hit pretty hard too.
I could definitely see the bandits staking out the lighthouse as a potential hideout. Of course, they wouldn't really be too interested for long, given the place has giant snakes and giant roaches.