Well, you aren't going to find pizza there. They have mac and cheese and mini frankfurter sausages as "designated" kids choices. But they can get anything from the buffet.
What I would suggest is to not let your kids even have a clue that you are the least bit concerned. If THEY think YOU think they won't like it, they won't like it.
The great thing about a buffet is they can try anything they want and if they don't like it, they can spit it in the fire (old family joke).