You ARE in violation of the lease if you have pets and have not paid a pet deposit as they require. I would pay the $300 and be glad they aren't saying something like, "NO SNAKES ALLOWED" and forcing you to choose between getting rid of the snakes or being evicted.

The violation of privacy is an entirely different issue and I'm honestly not sure how to pursue that. Maybe you can pay the $300 deposit...then demand a $300 compensation for the violation of privacy? It certainly seems like SOMEone was poking their nose where it had no business being. Maybe he went through your underwear drawer and read your private journal, too? Creepy...and worthy of a serious complaint. But I don't think you'd have a leg to stand on if you try to mix the two issues into one.