If you consider the Bahamas to be in the Caribbean.....

I've been to the Nassau Marriott (and posted here about it in late Feb of this year)....for a Plat, we were upgraded to an oceanfront room. The rooms were nice, not fancy, with 2 queen beds.

Many kid friendly activities at the Marriott and nearby. You didnt give the ages of your kids, but the pool has a nice waterslide. There is parasailing, jetskiing and banana boating available right on the Marriott beach. Kiddie golf and other activites as well. The water is calm, without waves.

Keep in mind that hurricane season is in full force in the Caribbean now, and especially from mid August til the first of November.

We've booked the Grand Cayman Marriott for next February...tried to get the Aruba Marriott but awards were already gone.