I am hoping that the drywall issue will work for you. I loose trust in drywall when the paper skin has been removed.
Anyway, I would suggest that you go to a Paint Dealer and look at the kitchen/bath paint. Sherwin has an excellent product that is latex and has an additive for anti mold, and works great in that area. Oil will take too long to dry, will smell and with the drywall situation, that moisture up there that long might cause problems with releasing.