I personally wouldn't recommend it... But each case is different, so you may be ok.
Just be cautious and maybe try them in small amounts.
Sugar and lactose are what give me bad flare-ups.
Unfortunately, each person is different. Personally, I have no problems with sugar, butter, or oatmeal. I would also suggest trying things in small amounts until you know what sets off pain or symptoms.
I don't see why not. Sure everyone is different but if you've been able to tolerate it in the past then you should be able to now unless you're in a really bad flare then the oatmeal may be hard to digest so take a bite and see in that case.