Pancolitis just means the entire length of the colon is effected. It's still UC. There are different degrees of severity. Mine was severe.
I am doing very well now five years later. Knock wood....I have not had pouchitis or any issues. I had a GI dr. who was a firm believer in the therapeutic properties of Pepto Bismal. Hope it continues to help you.
As for the cheerios, maybe try a little bit and see how it goes. Who knows, you may be fine with them. Just do it on a day where you will be home for a while! My hubby has a perfectly healthy colon and he can't eat them either. They send him straight to the bathroom!