I'll jump back in to say that the early advice I received from my Pouch specialist and the dietician who works in the practice was to go easy on refined carbs and get a good deal of lean protein. I do a lot of chicken - cutlets coated with corn flakes or potato flakes (Bob's Red Mill has a good product) which are also good cold. Pearl barley was suggested by the dietician and that has worked for me. It can also be used cold in salads.
Another thing to consider is rice pudding. It can be made with almond milk if you're staying away from lactose. Very easy to prepare. Also ok in a lunch box. If you're a rice pudding fan there's a decent brand of individually packaged product you can get in most stores: kozyshak
As for the Cheerios - I'm ok with milk, but also have found oat milk to be a great alternative. And I often add them to plain greek yogurt, sometimes with a bit of honey, because you just need crunch every so often.
I do peanut butter plain on bread with some protein powder, and either honey, grape jam or guava a jelly - small amounts just to mix it up, and no fiber. I can tolerate light whole wheat bread but not much if it. I also put PB on corn bread, which is easy to make and you can prepare it with little sugar.
And if you've made it to the end, here's my favorite J-pouch snack. Marshmallows seem to be well tolerated. As is rice. That translates into Rice Krispie treats for me, so I make them frequently and will sometimes add peanut butter. Never gets old.