We were there over the holidays. First of all, it's amazing. The girls and I kept getting teary just being there in Harry Potter world. They full on cried when we left because they want to live there.
PA food experience was good. Definitely talk to the chefs at the restaurants, because the people at the cash registers don't always know. We really loved how the chef at the 3 Broomsticks was very thorough in assessing risks. At Florean Fortescue's ice cream she could only have the butterbeer flavor, but luckily that's what she wanted. They brought it from the back,
We also were told she could have the turkey legs by email in advance, but then the chefs said no, which was odd.
The food court in the Cabana Bay Beach Resort hotel was awesome for allergy guidance. Lots of choices. DD wants to live there, too.
I'll try to come back and give more details.