I would add Amuse Bistro to your list if you favor quality (great flavors, careful preparation, fresh ingredients, inspiring tastes) over mere quantity (price per pound) . . . Patrick and Ivette are one of the best new introductions to the island . . .
I totally agree about Amuse. We loved Barefoot, but Amuse was our favorite new restaurant on our most recent trip. The service was great and we loved the option of ordering basically anything on the menu either small plate or full size. We went with small plates and had a great meal sharing so many different things... and make sure you leave room for dessert.
Boca Catalina Beach
Mangel Halto for Snorkeling
Welcome to the forum. You will absolutely love Carte Blanche. We were there in July and had probably the best dining experience we've ever enjoyed. Just be prepared for a long and enjoyable evening. We got there at 7:20 and left at midnight and enjoyed every minute!
I also agree about Amadeus. It is a great meal with terrific service. Be sure to end the meal with a "Lost Symphony" liqueur. The owner makes and bottles it.
As to the ATV rides, we had a blast, but some of the operators are less safety conscious than others. You may also want to consider a snorkel cruise. Our personal favorite is Roberto's Watersports - they have a booth in front of the Marriott properties. It's a smaller (tri-hull) sailboat than some of the other operators, but you snorkel in the same spots as the larger boats.
If you are at the Marriotts, you may also want to try Simply Fish. The food is great, but it is expensive and you can duplicate the meal for less elsewhere. We usually go because we stay on the Marriott property and it's very convenient, especially the first or last night there. The setting is also nice, as you're seated on the sand and watch the beautiful sunset.