Joanne,
That sounds like a such a fun trip! I love multi-generational visits to Disney. One of my favorite memories is of riding Mission: Space with my husband's Granny - who was in her 90's at the time!
You don't specify what your budget looks like, so I will try to recommend something for various price ranges.
For a Value resort, I would look at All-Star Music. They offer family suites which are essentially 2 standard rooms refashioned into one, and they include a kitchenette and a second bathroom which is great. A couple of these suites might work nicely for your group.
In the Moderate category I am torn. Caribbean Beach has been newly refurbished and would be my children's first choice, but Coronado Springs has also been refurbished and has a very rich, upscale feel to it (while still having a fun pool and play area for the little ones.)
For a Deluxe resort I would recommend the Yacht/Beach Club. They have an amazing pool that is really more like a water park - a 2 acre water park! They also offer a beautiful atmosphere on the Boardwalk, and a fantastic location just a short walk into Epcot or a slightly longer walk over to Hollywood Studios.
For a Villa, I would choose Old Key West. This is one of my family's favorite Disney resorts, and we are Disney Vacation Club members so we've tried them all. It is an aesthetically beautiful resort with a laid-back feel and very spacious rooms. You would also be able to get a huge house-like villa if you so choose, or smaller, adjoining rooms if you'd like a bit more privacy. We love the ability to park right in front of our room and, if you get a 1 bedroom or larger villa, you will have your own laundry room and full-sized kitchen as well.
Best of luck with your decision and have a great vacation!