Before heading down in December, I was nervous about our Chef Mickey ADR because I had been reading plenty of mediocre reviews. Something I realized was that the good reviews I was reading and have read since are from people with allergies and the mediocre reviews are from people without them. CM seems to be a huge hit for people with allergies. It was one of our favourite meals. It was also the only place DD12 (gluten, milk, egg among her intollerances) was able to get a baked good for dessert (delicious chocolate and vanilla iced cupcakes). Most do not have an egg free baked good. The chef was wonderful and the food delicious. We also had great character interaction which was what most complain about. We also didn't do any other buffets besides Tusker House which is completely different kinds of foods and many of the complaints were that the food was the same as all the other buffets. We ate dinner though, not breakfast. I would assume they can make the same waffles that are available everywhere else but I don't know what else is available for breakfast. I would assume likely bacon and some kind of sausage or ham along with fruits but that's just a guess. I'm sure the chef could get fruit.
We've also had great experiences at 1900 Park Fare. We've done breakfast there twice (before egg was figured out). They have plenty of meat options and they can do the waffles without milk and egg (they use apple sauce and apple juice) just like every place else. If I was to do a breakfast buffet at this point (we typically don't do breakfast TS meals any more), I think it would be 1900PF because I know they have a good variety of breakfast meats so there will be some good options.
We've only had dinner in the castle, not breakfast. They do carry Enjoy Life cookies (at least they had them in December) and I would think you could ask for some even at breakfast. Last I heard they carry Van's waffles for their allergy waffles. We use these at home and enjoy them, but I have trouble with the idea of paying those kinds of prices to get the same food I pop in the toaster at home, KWIM. I understand you'll get plenty of fruit, but I don't know what else (maybe bacon?). The castle was one of the places that didn't have nearly as many options for us at dinner though the chef did try to work with what he had. He just didn't have as many different kinds of foods to work with. We chose dinner there because DD12 is a real beef lover and the prime rib on the dinner menu looked good (it really was) but there really wasn't much as far as sides go.
I know you didn't ask, but one place I was told by a chef at the restaurant would not be safe to eat because of the sesame intollerance was Tokyo Dining. Not a lot of people ask about sesame so I thought I'd mention that one.
Another option to meet Mickey is dinner at Garden Grill. They have Mickey, Pluto, Chip & Dale. We quite enjoyed this meal as well.