Yes--you can use both themed pools at Port Orleans.
We were at Old Man Island (the pool at POR) nearly every day of our trip, and my kids (9 and 7) LOVED it! They loved the slide and the splashing bucket. Muddy Rivers is a nice poolside bar.
We used one of the quiet pools at POR once, when we were doing laundry. The laundry rooms are next to the quiet pools. It was a nice pool, but my kids liked the pools with the slides better.
One time we used the pool at POFQ and it has a colorful slide. My kids enjoyed it there very much, too. It has a fun Marti Gras theme.
If you have time, give both pools a try during your stay.