I had to eat gluten free the last two times I was at Disney, so hopefully I can offer some advice. Disney is really accomodating, and has a lot of options for people eating gluten free. You can call I belive WDW Dine, and have a list of gluten free foods at each location emailed to you.
I have found the table service restaurants to be awesome when it comes to having a gluten free meal. If you're eating at table service restaurants, note the people in your party who need a GF meal when making reservations. Remind them when you get to the restaurant, and the chef will probably come out and discuss what you would like to have. I had the best experiences at the restaurant at Saratgoa Springs (chef was super nice) and at Kona Cafe (GF breaded almond chicken, rolls, crab cakes, and ice cream sundae)
The counter services were hit or miss. They can be so busy at times, and some of the people don't seem to be too aware on what gluten is. They do have options though, so try and talk to the chef at each location. I actually worked at a food court at one of the Disney hotels last summer, and I know they have options stocked so make sure to speak with someone in charge. Hope this helps, and good luck planning your trip!
