Definitely contact Chef Chris. FWIW, I wasn't able to get ahold of him through the direct number that is listed on celiac sites (that I assume is the same as was posted here). It never went through. So I called Disney Dining and asked to be contacted by the "chef in charge of helping with food allergies". A day or two later Chef Chris called me and we had a great talk.
Even let him know that Uncrustables are chock full of high fructose corn syrup and corn syrup, which he didn't know (so even the chefs in charge of it don't read ingredient lists!).
If you are prompted to leave a message, BE SPECIFIC as to what you need, so that he can be prepared when he calls you back.
Lastly, don't be afraid to bring in food. If you need to bring in "fixings" for food, you'll probably need to leave it in a locker outside of the park, and of course you'll need a cooler. If you can just bring in prepared food, get a small soft-sided cooler and that should be fine.