There's gotta' be some bigger reason that the humans are doing this besides "other races bad". Because this is above and beyond a simple extermination.
MC has a lot more chemistry with Marie than that other girl. Them becoming a freaky mutant couple is probably never going to happen, but I want to see it.
Both the ghosts following the woman have bent backwards knees. Probably father/son.
Perhaps the mother had something to do with their demise, which is why they're haunting her.