I LOVE Disney in August!!! Yes, it's hot, hazy and humid...exactly as summer should be

Especially coming off the winter we just had--- Disney in August is the "anti- Polar vortex"
OK, down to details.
My first suggestion is to purchase 2 of these:
http://www.walmart.com/ip/Misty-2.5-Personal-Mister/19715437 They'll keep all 4 of you comfortable when it's most humid. They don't need batteries, weigh next to nothing, and can fit inside a ziplock bag in your purse or park bag.
Next, my husband and son swear by sneakers. Not me. I LOVE my Teva mush flip flops, and have converted both my daughters too. I walk all day long in those things!
http://www.sierratradingpost.com/te...String=s~teva-mush-flip-flops/&colorFamily=20 (in fact, that's a good price... I may just pick up a spare pair for our upcoming WDW trip

)
The best suggestion, though, is to be at the parks for rope drop-- about half an hour before they open. Spend those first 2 or 3 hours hitting all the rides you really want to see-- the lines are minimal and it's the best part of the day.
Then, at around lunch time, you hit the point of diminishing returns. It's hot, crowded, and time to head back to the resort to spend the afternoon swimming. It's a family vacation, and no fun if everyone is cranky.
Then get dressed for dinner and head back for a much more relaxed evening at the parks.
Honestly, it's rare that we have an issue with the summer heat at WDW. There are lots of air-conditioned rides and attractions.
Oh, and I agree about the ponchos. Stock up ahead of time. We normall figure about 3 apiece for our weeklong trip. I like
Walmart's better than the ones in the dollar store-- they come 2 to a pack and are more compact. (If you can't find child sizes, just tie up the sides of an adult sized one.) Some years we don't need them, but more often than not we do. When you do, remember one- in a bright color!!-- for the stroller. (A dollar store table cloth and some clothes pins works just as well for an empty stroller. Just cover it before you park the stoller. Lots of times we returned to the stroller, surprised to see that it had rained while we were inside.)
And mdinme, we'll see you at Stormalong Bay!