Re: Uncooperative participant
When confronted with a similar 'guest' I threw him out of class.
When asking a 'theoretical question of one of my seniors, "what if a higher ranking instructor from our organization moves to my city?" His answer was that I 'founded' the dojo, it's my place. In truth I probably would have welcomed the help, but the stance was interesting.
Some good ideas mentioned above.
If you can't solve the problem with his organization, then your problem appears with the Parks and Rec department. I would alert them to the safety concerns. I would also consider bringing the entire class to a responsible person at the department and explain that all of you will cease to practice there if he doesn't leave. You should use your credability as another Parks and Rec instructor. Do they want to start from nothing all over again to build a class?
Lastley if you feel he is that disruptive, you might consider a restraining order from the police, where he is not permitted to be near the dojo.