Have you tried her on the SCD diet, which purports to change the gut microbiome?
IBD-AID and SCD are essentially the same diet. IBD-AID is a derivative of the original SCD with a few tweaks like allowing oatmeal, occasional sweet potato, and tamari (soy sauce). This was based on research done by UMASS.
OP, how long have you been doing IBD-AID? I would say you can back off a bit on it if she is not seeing any improvement after a month or two. Journal everything (diet/medication/symptoms) if you can manage it. You may stumble upon a symptom trigger. There are some "legal" foods that are not tolerated by some people. Unfortunately, childhood IBD tends to be aggressive and there are not currently a lot of answers. I have UC and have been through a scare with my 8 year old which (hopefully) was nothing. Sorry your family is dealing with this. Diet may play a role but that has not yet been firmly established. Trial and error is all we have. General consensus is that fiber and prebiotics are beneficial (if tolerated) and processed foods are probably not good. Animal protein has been linked fairly strongly to IBD but this contradicts the benefits reportedly fro SCD/IBD-AID. Most dietary studies are poorly designed.
Dig through the posts here and you will find various supplements etc that may be worth trying. This is also worth a read: