I wouldn't be surprised if that ends up happening down the line. It hasn't taken that long for totally-not-Mordred to go from "WHAT THE HELL? YOU STOLE MY BODY!" to bantering with the group like she's starting to belong there, despite the fact she's effectively a ghost now, so I'm guessing the other girls who get possesed are going to have similar personality transformations once they're forced into ghosthood - and start spending time around a group of friends who aren't raging assholes.