Hi, Chantel!
Woo hoo!
Not only are you heading to Walt Disney World with your four children, but you are bringing two princes AND two tiny princesses...that is so fantastic!
My first trip EVER to Walt Disney World was when my son was 5 months old. My daughter was 3 1/2, so I knew that her dad and my in-laws would be able to take care of her, but I was worried about nursing my son. Boy, was I spoiled; Walt Disney World has created
Baby Care Centers, which feature changing rooms, kitchens with microwaves, feeding areas that are baby and older sibling friendly AND private nursing rooms with rocking chairs. I had no idea then that this was unique to WDW, but I am forever grateful that there was a lovely, private space where I could nurse my baby in private, with soft music, muted lighting, lovely artwork on the walls and comfy rocking chairs throughout the room. Siblings and spouses can wait in the adjacent room, so everyone has access to what is needed throughout your stay.
These Baby Care Centers are often located as near to the entrance of each park as possible, usually near the First Aid Center, as well. Check the map of each park to locate the Center; I'm sure that you'll be impressed with what you find there. I know I was!
We often grabbed a snack for the older sibling, who could enjoy it in a climate-controlled area adjacent to the nursing room, and Dad would supervise while Mom nursed. It's a great way for everyone to unwind, cool down (or warm up!) and relax while Mom and babies are refilling their tummies!
Have a wonderful trip, Chantel! Send more questions as you think of them; we love to help!