Take a misting fan with you and fill it with ice water each morning. We also had a clip on fan for our son's stroller, but he wouldn't leave it alone. Our September trip was a hot one. You can read our trip report below.
Also there were lots of love bugs flying around. Someone said they were attracted to people wearing white shirts. Not sure about that, but I wasn't wearing white. They were harmless (think lightning bugs), just a slight annoyance.
Also we took an insulated sippy cup every day to the parks. All the restaurants were really nice to give us ice water. We'd fill our son's cup and then my husband and I would drink the remainder.
We stayed at CBR. Used their pack'n'play. There's a picture of it in our trip report.
Also please stop in the toy store in the UK at Epcot. Every little bit pooh, tigger, and euyore stop in for visits with the kids.
Got our son's first hair cut at MK. Long wait though. And for some reason, they made us pay in cash. But we got to video tape it. They gave us a certificate and some clippings of his hair.
We have a picky eater so we got a loaf of bread in the resort gift shop (also milk). We made peanut butter sandwiches and took them plus some applesauces to the restaurants with us. We had a soft little cooler that sat in the basket under the umbrella stroller.
Enjoy your trip!
Cheryl