DD11 has allergies to dairy, egg, tree nut and peanut allergies. We have had pretty good luck at TS restaurants getting her pasta that she can eat. If you let them know your allergies, they'll let you know what you can have. There are some pastas that are generally made with eggs (e.g., papparadelle, fettucini, elbow macaroni). We were have never eaten at a sit down restaurant where she could not get plain rice, pasta, or fries. She prefers pasta with olive oil. Not a problem at most places. The noodles at Teppan Edo had egg in them when we were there. DD11 was happy with rice. Udon noodles sometimes have egg in them. Most places also have a plain grilled meat option. My daughter choice, chicken, is usually available.
If you provide a list of some of your son's other favorites, I'm sure your fellow DISers will be able to provide you with a little more information about them.
BTW, thanks to all the other board members that provide allergy information in this forum. It seems to be the best way to keep up on changes at DWR between trips.