I believe the issue is that the two businesses are in direct competition with each other so they are more sensitive to intellectual property. It would be like Univeral introducing Macky and Millie Mouse, Goofball, Pluton and Dan the Canadian Goose. For their part, Disney is rather aggressive about going after anyone that either uses their image or infringes on it so I cant see them riding the coattails on a competitor's idea. Really isnt anything to be gained by it anyway.
Regardless, dont want to turn this into a thread about copyrigh laws and how far Disney could go with the wizard idea as it's far more likely they rent out the space for someone that wishes to utilize the concept anyway. When the Weasley's open their joke shop in DTD, they can fight Universals corporate lawyers!![]()
It's actually not "copyright" law that would be at issue here (doubt Schussler would be dumb enough to directly rip off characters/names), it's a closely related legal principle called "trade dress." And it's a nebulous area, particularly with restaurants. One taco place succeeded in suing another for copying their "look" and "feel", but the parent company of Orlando Alehouse and Hooters have had no luck suing people who basically cloned their restaurants (anyone who has been in a Winghouse can tell it's pretty clearly a Hooters clone, but the court let is slide).
Hard to say if a Universal lawsuit against Schussler would work considering neither spot has even opened yet. It would come down to the details, and both sides would probably end up with pretty hefty legal bills. But there's no question Disney has a history of opening attractions that closely mimic other attractions in the greater Orlando area (PI/Church St. Station, Living Seas/Sea World, MGM/Universal, AK/BG...).