Instead of making it a rule not to use enderpearls and trying to enforce it, you can just stand on the residence and type "/res set enderpearl f". This will make it so that it won't be possible to enderpearl.
If I could I'd love to be a teacher, over time I have developed many strategies on how to fight mini-bosses and such
Also, you can prevent players from using potions by a buff flag. (I can't remember the command though)