I've heard a lot about these guys as well- CanisD is right, they are a bunch of lawyer-types who incite a riot to further their goals of profitable lawsuits, then hide behind the non-profit status of a 'church' in case there is any chance of them loosing. After all... what can you get if you sue a non-profit organization?
The members are also indeed crazy as outhouse rats, and most are related to the pastor in some way.
Good luck in your efforts- this troop will be praying that you guys can situate your counter-protest between them and the actual funeral... perhaps with some large screen curtains to help block the view?