i agree that you'll do fine eating at WDW.
in fact, i remember feeling very pleased with the meals i ate at the sit-down restaurants. i'm gluten-free, dairy-free, and a few-other-free's, too, and i remember that it felt GOOD to be able to eat a meal at a restaurant with family like a "normal" person. i felt very satisfied, and enjoyed each meal quite a bit.
i didn't try to figure out how to eat at counter service restaurants, though. i'm sure it can be done, but usually we stopped there when we wanted a fast meal, and i didn't want to slow things down by having a special meal. however, if it was pre-paid on a dining plan, well then, i'm sure it would have gotten figured out!
enjoy!!!!
-dj