#1.) This is going to sound harsh... I do not mean to affend you... but it was pretty stupid to have the snake out in public like that. You certainly weren't doing the snake any favors, and you obviously didn't do yourself any favors either.
#2.) If caged pets are allowed, and the landlord was aware of you having the BP in the first place, you shouldn't have anything to worry about.
#3.) Don't let the landlord bully you. There are a lot of vacant apartments out there right now. They want your business. If they try to bully you by saying you must get rid of the snakes or move, then call their bluff. Tell them that you will not get rid of your pets that are allowable by the terms of the lease you agreed to, and that you refuse to move. The burden will then rest on their soldiers to attempt to evict you if they so choose. The odds are they aren't going to do it... and if they do, so be it. Like I stated previously, there are plenty of vacant apartments out there right now. So much so that you will likely get a free month or at least discounted when you move.... so it may not "cost" you anything to move.