RFC does have breakfast, but I'm not sure what time they open. We had breakfast there last Dec about 8:30am. I remember we had to ride the early morning character bus to get there, so the park wasn't open yet. I would assume they would start serving about the same time Donald's does. We had ADRs but probably didn't need them, as there were lots of empty tables.
Oh! FYI: We had wanted to make ADRs for the RFC at DTD, but they do not serve breakfast (only the one at AK).