Welcome aboard, Martha!
We have visited the Atlantis Resort in Nassau when we've come into port there with Disney, and let me tell you, Disney offers some really great Port Adventures to Atlantis! Since you've got a wide age range of kids, you might consider the
Discover Atlantis adventure. Everyone rides a motorcoach to Paradise Island where you'll be led through the huge resort to the aquarium which is themed like the ruins of the lost city. It's one amazing aquarium! You'll get a wonderful tour of the aquarium and have time to then explore the resort on your own. If you think some of the group would like to relax on the beach too, do the Beach Day and Discover Atlantis combo tour. However, in my opinion, the beach there is okay but nothing compared to the stunning beach you'll enjoy at Castaway Cay.
On Disney's Private Island,
Castaway Cay, you can choose a Port Adventure if anyone is up for it, but the rest of the group can simply set up camp at a spot on the beach and take part in tons of activities that are all included. My family loves the crab races, Character Dance Parties, Family Whale Dig (think - learning to be a paleontologist), waterslide fun at Pelican Plunge, splashing with the little ones in Spring-a-Leak, oversized games at In Da Shade Games, and lots of beach and ocean time! Renting bikes or snorkel gear is easy to do that day, no need to plan ahead, so a few may choose to enjoy that too! You can all do what you'd like that day and still be in the same area! Lunch at one of three open air buffet restaurants on the island is included too, (all serving the same selections), so no matter where you are, it's a quick walk to grab some food and gather the family together again!
Have such fun, Martha!
Marcy