I would recommend the Vista or Horizon for sure. In 2019 Vista will be doing alternating 7 night eastern and western itineraries out of Galveston. Horizon will be doing 6 night western and 8 night Southern itineraries out of Miami. I highly recommend the 8 night Southern, we loved that on the Vista last year. Next behind that, is recommend the Breeze, I believe she’ll be doing alternating 7 night western and easterns out of Port Canaveral. From what I’ve read the Magic and Dream are also great ships but I’ve yet to try them. Ive spent 22 nights on Vista and have yet to try everything that she has to offer, there is so much to do. We’re hoping to finally try it all when we board Horizon in June 2019.
BTW, when exploring room options, Vista and Horizon have way more connecting rooms than all the other Carnival rooms. They also have Family Ocean View rooms that have a full 3 piece bathroom, plus a second 1/2 bath that has a shower and sink. The Family Harbor area also has some great features, especially for large groups like yours. There’s an exclusive lounge with snacks, breakfast and 24 hour soft serve ice cream. There are also video and board games in the lounge. The Family Harbor Suites are really great cabins as well. They are considered Cove Balconies that many Carnival cruisers just love. They are on the 2nd deck so you’re very close to the ocean and people just love them.
The Disney Fantasy used to be my favorite ship until I sailed the Vista, now she is my favorite ship, by far. I still love DCL, but definitely love CCL as much.