I plan on putting Luka as borderline insane or just really depressed for his next mission (the one where he has to protect another little girl), not even trying to hide his emotions.
I can't wait for P5 either, although I'm still in the middle of playing P3 right now. Good to see another fan! Have you played Arena? That game drops all sorts of hints towards the sequel. Or a sort of spin off game. Whatever they plan on doing, they're gonna continue the P3/P4 story.
I've got an idea for what to do about the villagers, but I wanna run it by you first. Is it alright if when they leave for the volcano, Luka's mind is completely focused on what he is going to do about them when the little girl he saved first, now recovered, runs up and hugs him. Then because of what is occupying his mind and the fact that he has used his power a lot after not using it for a long time (thus lessening his control over it) he accidentally inflicts a plague upon her so that when Luka and Spencer get back they find the villagers all killed by the plague?