When my DGD suffered from dairy and egg allergies, Disney could make her waffles and pancakes. The mix was Bob's Red Mill and it was gluten free. I will not say it was gross because the poor kid had not had pancakes for so long that for her, they were delicious! I was not a fan. I never could make the appropriate substitutions for both the dairy and egg so these were a godsend for us. I made them daily for her when we returned.
As to your allergy question: please do not do this unless you have an allergy. Disney takes allergies very seriously, and trains their chefs in over 40 food borne allergies. They need to use a special area in the kitchen with special cookware. IT is no joking matter in Disney kitchens. Once you state you have an allergy, you will nto be served anything with that allergen present.
Now I have been told I am rude when responding, so please take my feedback in the spirit I intend. I am not trying to be snarky. Please do not use an allergy in order to gain special treatment. Disney is one of the few food safe places for people to go on an extended stay if they suffer from allergies. If people take advantage and lie about their allergies in order to gain special treatment we all run the risk that Disney will pull back these special services that they offer. If you want an item that is offered as a sub if there are allergies, order it when you get there. Most likely the CM will gladly make the change for you.