I just got off the phone with the Cons.(MS?)desk at the portofino. He said that their restaurant there has two characters usually Woody and Scooby Doo. NO minimum and no buffet like Disney.
He also told me that the restaurant in Islands Grill something or another has character dining between 12-2 first come first serve. He also said that they usually have more than two characters. And by the way Port and HRH guests have priority seating. So be sure to flash your key.