My son is allergic to peanuts and we have eaten at Boma many times. Tell your server about the allergy, and the chef will come out and actually walk you around the buffet and point out everything your child can and cannot have. We haven't seen that many peanut dishes there, but last time there was peanut rice. There are also many dishes with other nuts, but they are usually labelled, and if not, the chef will point them out to you. Most desserts will be off-limits, but ask the chef about getting your daughter some ice cream. They have done that for my son before, but now that he is 12, he is too embarrassed to be brought something different!
Another place that treats allergies really well is the Plaza Restaurant in Magic Kingdom. They actually will bring out this HUGE binder that lists every food they serve, so you can check for allergens. It is actually overwhelming! Also, the last time we were there, a manager came out and said he was going to personally prepare my son's food to make sure it would be OK. It was really neat, although again, my son was a little embarrassed.
The main thing for you to remember is to bring your daughter's Epi-Pens EVERYWHERE!!!!
Good luck; I think you will find Disney to be very accomodating to your child's allergy!!