I think this idea is feasible. Don't do it in a way that gives players access to moving/removing peoples housing items.

Instead do something like adding item 'TP' and then allowing the player to use this on a tree or bench - it overlaya the item with a tp lookm but nothing is moved.

The owner can then right click -> clean to easily remove it when the event is over. Or maybe there are event rewards based on people cleaning up. 'Naughty' rewards and 'nice' rewards - like trick or treating.

Could have effects like crackers in mailboxes so next person to use it sets off a small explosion. Tp trees and benches. Spray paint a halowwen image on a wall or something - i dunno.

But it doesnt need to give players access to move or remove housing items at all.