I was there with DS in May - he was 13 months at the time. We had a great time! For food, DS was eating regular food, so I normally ordered something he and I could share or got an extra side for him. Sometimes, I would get him a kids meal if I wanted a salad. DS is really good with food, so we did not any trouble.
I also made sure I had lots of snacks. I have a snack trap, and if I fill it with cheerios, DS is very happy. Also, little snack size bags of animal crackers or similiar things worked really well.
We took it easy - normally had simple breakfast in the room, headed out to a park. We then got back to the room by 2 for a nap, and then swimming or relaxing, or sometimes heading back to a park in the pm for a couple hrs.
For the heat - I dressed DS in lightweight closes, kept offerring him water, I had a stroller fan and a misting sprayer - he loved it. If he seemed to get hot, we'd take a break in Baby Care. Sometimes, he'd have fun playing for a bit with Baby Care.
He loved Magic Kingdom's Pooh's Thoughtful spot play area - I put him in swim bottoms and a swim diaper, and he'd get soaked.
Overall, it was a great trip. You should have a fun time.