We took our daughter when she was 2.5yo. All the buffets are free for children under 3. At that time we ate at O'hana character breakfast and it was terrific. DD was so busy with characters that she ate very little. Our wonderful server gave us a juicebox and banana to take with us because she knew she would be hungry soon. The only character she was apprehensive about was Goofy. She loved the others. We took her again in March, and she loved all except Captain Hook, Rafiki, monkey from Jungle Book & a tall bear a(??).
As far as other meals, I often shared a portion of my meal, or odered her just a cup of soup, or a side of mashed potatoes or green beans. To be honest, I don't think the child ate lunch (at age 2.5) the entire time we were there, as she always slept through lunch and we would end up buying chicken nuggets or something for her later.