The plans sound terrific! I'm sure you will turn your Mom into a WDW-lover on this trip! Rob and I really enjoyed our dinner at PALO on our cruise (13 years ago, sheesh!!). The brunch does look incredible, but with it being such a short cruise already, I maybe wouldn't worry about trying to fit that in, too.
Snorkeling off
Castaway Cay is really awesome. I loved finding the sunken Mickey statue, and now there is a Minnie to find, as well. We snorkeled out to the end of the fenced area and there was a huge hole in the fencing. There was a gigantic scary looking fish with huge teeth, which I was convinced was a baracuda. I have never swam so fast in my entire life, I was back to shore almost immediately. Rob was like, "Where the heck did you go?!" He still insists I imagined the killer-fish. Just be careful out there in case I'm right! LOL