People call every damn theory predictable

What if this is the ending?
Miss Bean is the killer. She haunts the campus with her fatness. She killed Melanie because she treated her like ****. Then she faked her own death to frame Chanel for murder. She also wears a corset to fit into the costume. The baby in the tub is Feather. The survivors are Feather, Melanie, the Detective, Chanel's Asian and Chad's Father.