I like “Monster’s of New Haven High” it describes your WIP well. Also “Monsters and Midterms” has a nice ring to it. I don’t think the other names describe your WIP as well as these two. Like, I wouldn’t think it’s about a high school with monsters and people (having to mingle inconspicuously) .
Maybe something like “The Monster Merge: Homecoming or The Monster Merge: Senior Year”. I can’t remember what year MC is supposed to be in. So if senior year is inappropriate, you could just fill in what year MC is supposed to be in. I also think something like “A Monsters Senior Year” would make a suitable title.