So the Steel Cut oats looks like the third image.
You can get the Costco economy size or I got the tin from Mariano's which is a super here.
They look the same but I got 1/3 of the quantity as Super's rip you off.
Oats is under his approved list
http://www.ibsdiets.org/fodmap-diet/fodmap-food-list/
It is also a gluten free item, so as long as it wasn't processed with other stuff. You should be ok.
As far as cooking it.
You boil water in a pot. Add a pinch of salt.
When it reaches boil you throw in the oats.
Put the lid on, turn the heat off
and leave it for tomorrow morning.
The overnight will allow it to soften and absorb moisture.
Then in the morning, you can heat it up and it should be ready in 5-10 minutes.
The oats don't taste like much, so the irish pour cream and add brown sugar.
In your case, you will need to get coconut milk.
This is also under his approved list and should be fine for you.
You just drizzle some, no need to drench it. You can always add more.
For sweetner you can use brown sugar.
I personally order Maui Sugar. The price is the same as the Super, it is made in the USA and tastes twice as better.
http://store.kauaicoffee.com/premium-maui-gold-raw-sugar-p103.aspx
optional
Add some strawberry bits.