Yes, everyone dines from the same buffet. There is a kids area, but the anyone can eat from it. It's lower to the ground, had plastic plates and has more 'kid friendly' selections like chicken nuggets, mac and cheese, fries, etc.
All buffets at WDW have a section with kid-friendly foods (chicken nuggets, mac and cheese, etc). But anyone can choose from any part of the buffet. Kids aren't restricted to the kid-friendly foods, and adults can eat the mac & cheese, etc, if they like.