We just went for the princess breakfast last week and here is what they had:
Brought to the table: scrambled eggs, potato casserole (a scalloped potato with cheese type thing), sausage and bacon - they will bring you as many refills as you like, although we didn't get seconds on anything
At the buffet - little cubes of cheese (when we were there, they only had one type - it was a white cheese), bananas, grapes, strawberries, cinnamon buns, croissants, bisquits and raspberry danishes
Drinks: apple or orange juice and coffee
We were a little disappointed in this meal. While the food was okay, nothing was really good. The princesses were very rushed. They only said a few quick words and then they were on their way. The restaurant is big, so I realize they have to keep moving, but they really, really rushed.
We saw Belle at the door, Mulan, Ariel, Aurora and Jasmine. None of the princesses are guaranteed.
Be sure to make a reservation - this is a popular character meal.