I would say that Chef Mickey's has the most characters and they are usually Donald, Mickey, Minnie, Pluto, Goofy (and Chip and Dale). That's a good mix for boys and girls.
1900 Park Fare has an excellent breakfast too with a wider variety of characters which can include Mary Poppins, Alice, Mad Hatter, Pooh and Tigger.
We loved Liberty Tree Tavern for dinner. We thought the food was good! It was Minnie, Goofy, Pluto and Chip and Dale.
Donald's Breakfast in Animal Kingdom is good too with Donald, Goofy, Mickey and Pluto.
We like 'Ohana breakfast too with Mickey, Pluto, Lilo and Stitch.
With the ones already mentioned, that gives you plenty of choices. Good luck deciding!