Hi there Kimberley,
Well, there are no bad choices here. I agree that the Pool at the Caribbean Beach Resort is fun-tastic, and so is the one at Port Orleans!
Port Orleans has two sections: Port Orleans French Quarter (POFQ) and Port Orleans Riverside (POR). At POFQ, which has a 'Mardi Gras' theme, the pool is shaped like a giant sea serpent and you can slide down his long tongue or his tail!
Check out this link to see more. At Port Orleans Riverside, the theme is like 'rural Louisiana'. The pool has a relaxing feel of a meandering river. Of the two, I think the POFQ 'serpent' pool is great fun and this is the one I would choose for our family.
If your seven year old is a pirate fan, I would have to agree that you just can't beat the pool at the Caribbean Beach resort!
Kimberley, again all I can say is that there are no bad choices here - whichever you chose, you will have an amazing time!