Hi Aubrey,
Thanks for your questions! Your magical Walt Disney World vacation will be here before you know it. \
I just got MagicBands for my next visit, and they are the new 2.0 design. It is my understanding that all guests are now receiving the updated version.
Your niece and nephew are at fabulous ages for a Walt Disney World visit and will be able to do many of the rides and attractions. Some of my favorites for that age group (okay, and for adults, too) are
The Many Adventures of Winnie the Pooh, Dumbo, "it's a small world" and the Under the Sea -- Journey of the Little Mermaid at Magic Kingdom;
Frozen Ever After and
Journey Into Imagination with Figment at Epcot; Kilimanjaro Safaris and
TriceraTop Spin at Animal Kingdom; and
Toy Story Mania! and
Voyage of the Little Mermaid at Hollywood Studios.
You may find this guide to
visiting with preschoolers and little ones useful. It has recommendations on not only rides but also entertainment, dining and other activities with little ones.
Thanks for stopping by the Disney Parks Moms Panel, Aubrey. Please let us know if we can offer any other advice as you make your plans. Enjoy!
Wilma