I know that the popcorn is gluten free.
Dole Whip
certain ice cream flavors at Gibson Girl - tell them that you have celiac disease and are allergic to gluten and they'll scoop it in the back with a special scooper that is not shared with the non-celiac-friendly ice cream.
frozen lemonades
At the Jack Jack Cookie Num Nums stand on Pixar PIer, there's a gluten-free cookie that's prepackaged. It's lemon with a raspberry filling.
Plus, there's a big list of gluten-free foods at this website...
http://disney-eats.blogspot.com/p/disneyland-parks-gluten-free-list.html
We've gone to DL before with friends who eat gluten free because 1 of them has celiac disease. They had zero problems. Eating gluten free at the quick service locations was easy. Sometimes they just had to wait a little bit longer for their food to come out because for things like fries, they cook the fries in a special fryer that is ONLY used for fries (so no breaded products are in the cooking oil).