Special Diets at WDW is incredibly accommodating--I'm sorry you haven't heard back from them yet! My daughter and I both have celiac disease, and our dining experiences at WDW restaurants have been nothing short of spectacular. Just follow the recommendations already mentioned by members above, and everything will be fine! We honestly can't wait to return for the food--we totally felt "normal" there and on a nine-day trip neither of us got sick once, which was truly incredible to us, considering we never eat out at home for that exact reason.
Additionally, there is a gluten free Disney app we found extremely helpful, especially in selecting quick service meals.