You won't need to bring a crib sheet, the GF will provide one. If you do want to bring your own, you'll need to bring a pack 'n play sheet. The cribs provided by the GF "look" like cribs, but the mattress is the same size as a pack 'n play. There are no facilities to sterilize water for formula in the rooms at GF, since you need to boil it for at least 5 minutes for water to be sterile. Unless your child will be less than one month old, there is no reason (unless medical) you need to be providing sterile water for powdered formula. You can either use the tap water, or if you still are concerned, use bottled water that won't cause you any problems. Also, when I was traveling with my young infants, I brought my formula and diapers from home. I packed it in my carry-on for the just in case flight delays and then I had more room to bring home stuff!!!! Powdered formula doesn't take up much room, and I always bought the HUGE can of Similac and since that can lasted me at least a week, it was all I needed. I wouldn't count on being able to buy formula inside WDW, since they have an arrangement with Carnation. I have read other posts of people being able to find some Similac products, but if you use a different brand that those two, bring your own, or you'll have to stop at a nearby grocery store for your supply.