Hi Gina!
Welcome to the Disney Parks Moms Panel! How fun that you're bringing your Mouseketeers to Walt Disney World Resort! There is nothing quite like experiencing the Most Magical Place on Earth with your child. Pro Tip: Take advantage of
Disney's PhotoPass Photographers - these professionals are stationed all around the World (well, the Walt Disney World). As a parent it's so nice to be present for the memory making, both by being in the photos and by not having to be the one to worry about getting the perfect shot. They'll even take a picture with your camera if you'd like!
Planning some pool time in to your Disney Days is a great way to let the littles get some wiggles and giggles out!
Disney's Resort Hotels do provide life jackets in various sizes for all ages. (The really soft foamy kind.) These are found near the gated entrance to the pool area on a life jacket rack. In my experience life jackets have always been plentiful. My son first met Mickey at 14-months-old, and I did bring our circular pop-open baby raft as I was worried the life jackets would be too big on him. There isn't a pool rule specifically against floaties and other small pool toys, and our float seemed fine to have as no one called us out about it. Bigger giant inflatables, however, are not allowed. I would pack your own as your resort may not sell the specific floaties your children use back home.
Most resort hotel pools have children's splash areas, or a shallow kiddie pool. Bring a few water-safe toys for these areas, like a dive stick or even a plastic cup to dump water. Pro Tip: The bigger pools are heated to 82 degrees year-round. However, depending on your resort hotel, the children's pool may not be heated.
I hope this helped, Gina, and We'll See You Real Soon!
~Kristen