I think this is one of those cases of "things change." Now that you have arthritis to treat, you have more than just your pouch to deal with. Maybe you will tolerate NSAIDs, maybe not. Unless you have had past experience with intolerable GI side effects, you just cannot know if it will be an issue for you.
Yes, they will increase your risk for pouchitis, GI bleeding, liver inflammation, heart irritation, and more. But, you also need to be able to function and live your life. I was able to tolerate high dose NSAIDs for years before I had to stop them due to liver inflammation and pouchitis. By then, other treatments became available to me and I switched to them.
So, for me, it was worth it to take them, even knowing it might not be for very long. I still take ibuprofen or Relafen when I have a flare, but I limit it to two weeks now.
Jan