Chef Mickey's at the Contemporary has a full buffet. Mickey, Minnie, Goofy, Chip and Dale and sometimes Donald are there. It can get very crowded and noisy but it's fun.
The Cape May Cafe at Beach Club also has a nice buffet with the things you're looking for. Minnie, Goofy and I think Chip and Dale are there in beachwear - really cute.
The 1900 Park Fare at Grand Floridian also has a nice breakfast with Mary Poppins, Alice, the Madd Hatter and Tigger. (At least, that's who was there last June.)
If you have little girls the Princess breakfast at Norway in Epcot is also really nice.
As I recall Ohana was the only character breakfast that didn't have the usually Disney buffet.
Have a great trip.
