Utilize the dresser drawers
Try and use luggage that will stack inside of itself and store under the sink or on the floor in the closet area.
Collapse the pack and play when not in use and when in use place between the beds or next to the table.
Bring an over the door shoe bag/holder to put all your toiletries into.
Bring collapsible net style laundry bags for dirty clothes.
Bring a couple of plastic bins to place on the dresser, nightstand & table to keep track of spare change. cell phones, cameras etc.
Use a bin for all diaper supplies so that you can place it on the top of the dresser or shelf in the closet and have everything you need in one place. Same for bathtub stuff for the kiddos. I love plastic bins, place them in your suitcase and then pack them full of whatever is going into that suitcase. Then when you get to Disney, unpack as much into the drawers as possible and use the bins for keeping the clutter under control.
the stroller may also need to be collapsed when not in use and placed under the window in your room, in the years of having both a stroller and a pack and play we were cramped but did okay. We did not collapse either one, we used the stroller for back pack, camera bag and diaper bag storage when we were in our room and the pack N play got all the toys, stuffed animals, blankets etc. during the day to be distributed to their owners for night time use.
Have fun