Hi there, Evie! This sounds like a wonderful birthday celebration is in the works. Let's see if I can help you get on with the important part of the celebration - the part where no one worries about stuff.
Disney's Animal Kingdom Lodge has a really wonderful club level lounge. The Kilimanjaro Club Concierge offers planning services even before you arrive. One of the key features of this for you is going to be having the opportunity to discuss with them your daughter's allergies. Whew - we can breathe a little easier.
In some cases, they will have a member of the culinary staff from the lodge reach out to you. I have friends who have a son with gluten and nut allergies, and they were able to provide them with several breakfast items, chips, snacks, and even some special evening treats. You'll have the ear of someone who can guide you through the options and let you know what they can do to help accommodate your daughter's specific needs.
I also recommend making note on all of your dining and hotel reservations that your daughter has
Special Dietary Needs. It gives a heads up to the restaurants, allows them to help you navigate the menu and options at your dining locations, and will give you the peace of mind of knowing that the information is out there and someone will work with you to give your child the best dining experience.
Now you can start thinking about the fun stuff! Thanks for your question, Evie.