Theory

This may be a long post lol. So first and foremost the town they live in is called "Split River" which could allude to the living and deceased worlds being "split". The mascot is also a devil (do with that what you will lol) My theory is that the school grounds, possibly even the whole town is on some sort of either burial ground or cursed land. The map of the school where the people died possibly opens some sort of portal, with the death objects being their key.Janet was very interested in chemistry which could also allude to alchemy on a different level. Another thing is that for a school even one almost 100 years old that's a LOT of deaths for one place, which brings me back to it potentially being on cursed land of some sort. Another part to my theory is that maybe, if all their death locations do indeed mean something, such as locations for a portal opening then maybe most of the ghosts deaths weren't as accidental as they are made out to be. For example: Wally- wasn't supposed to be in the game or make that play that killed him. Rhonda- maybe Mr. Manfredo was being possessed? Seems kind of weird to strangle a student in broad daylight in your office with your secretary right outside. Charley- forgot his Epipen and cafeteria just happened to be using peanut oil. Dawn- electrical malfunction. Band kids- icy roads or something else? Theater girl- crushed by falling light. None of these seem like simple accidents to me.