We went three weeks ago. We just went to Walgreens before getting to Orlando and got those ready-for-use formulas in little 8 oz. cans, and DD (10 months) was fine with that. We warmed them up at the Baby Care Centers, or most of the time she took them as is at room temp. They were about $10 for a 6 pack, and were easy enough to carry around in our bag. I would definitely bring my own, because it's expensive there. But if you don't mind the price then go ahead and purchase them there. I don't remember if they have the specific brand you were looking for.
If you're looking to pack light, I would suggest this great bag I absolutely loved taking to wDW. It's a stroller tote from One Step Ahead, and it attaches to the stroller handlebar. it was nice and slim, but fit diapers, powder, wipes, baby food, and 3 cans of formula. It was great, I didn't have to dig in the stoller basket for anything.