I agree that the Apriso is a surprising choice. If the idea is to deliver the medication to the pouch then Canasa suppositories or mesalamine enemas would hit the target more reliably. It also seems like you may need treatment along the whole GI tract, given your mouth symptoms, so targeting the pouch may be insufficient.
It’s okay to pay attention to your diet, and it might help a bit, but it’s useful to know that it may also have little or no effect. You can drive yourself crazy turning knobs that aren’t connected to the machine.
I hope you feel better soon!