Hi, Cheri! What an awesome Grandma you are!
The first thing I'd do with your trip coming up so soon is to make sure you have your dining reservations in place. When you make your reservations - which you can do online by visiting
Disney World Dining - make sure you note that you'll be celebrating the birthdays. There may be some pixie dust sprinkled during your meal - maybe in the form of a dessert or card from the cast members or even some pixie dust on the table.
If you haven't noted on your reservation that you are coming for these celebrations, let them know when you arrive. You may be able to pick up your birthday buttons at the front desk when you check in, which will save you a trip to guest services.
There are also some wonderful ideas for birthday celebration ideas at
Disney Floral and Gifts. You can plan a fantastic surprise for your grandchildren on just about any budget!
I hope your vacation celebration is absolutely magical in every way!