IMO the toppings bar wouldn't really appeal to a picky child. The ones I've seen (Cosmic Rays & Pecos Bill) consist of tomatoes, lettuce, onions, grilled onions and mushrooms. No one really went wild at them... I would instead select CS locations that offer variety and scope out the menus at allears.net to pick places that have items your kids will like.
My recommendations would be:
MK - Cosmic Rays
Epcot - Sunshine Seasons (although we LOVE eating around the world. We get a single lunch item at each country to share and get to taste lots of different things)
AK - Flame Tree BBQ (I think my FAV CS location)
HS - We did Studio Catering Co this year - the pulled pork sub was decent, kids got their first PB&J of the trip there.
DTD - Wolfgang puck express - The pizza on the kids menu is large enough to feed 3 people. Seriously! Everything was excellent here!
Our Authorized Disney Vacation Planners are here to provide personalized, expert advice, answer every question, and uncover the best discounts.
Let Dreams Unlimited Travel take care of all the details, so you can sit back, relax, and enjoy a stress-free vacation.