I went August 19 this summer. It was Buster Poindexter hot, and it rained a good bit on and off all morning. BC was just wonderful to come home to, as ever, but especially so in these times of park hopping restrictions.
Location is HUGE. I sincerely believe that it can make the trip. It’s so nice (and now essential) to be able to go back to the hotel midday, or hop on Disney transport and be whisked to a park. Imagine being ready to go home and having to pack everything and everyone up, get in line, take a long ride, amd then have to schlep to TTC.
Epcot area resorts solve so much of that. So easy to walk to Epcot, the water and boardwalk are so nice to relax near, and HS is a super quick boat ride, or a walk around Boardwalk (Walking Path Shortcut
If coming from BC, head over to Boardwalk via bridge towards ESPN Club. Walk past ESPN, Ample Hills, Bakery, etc. until you get to the Surrey Bike rental kiosk. Take a left after you pass this, just before the Screen Door store. You'll pass by Wyland Gallery on your right and then take a quick right. Health club and game room will be on your left and you'll come out by the clown slide pool. Stay to the left around the pool and you'll run right in to the pathway to DHS. If you miss the pathway you'll be in the canal!)
No, it’s not particularly convenient to MK. And I realize that the littluns are happiest there. HOWEVER: MK is a madhouse at the moment, with limited entertainment options to thin crowds. The hour leading up to HEA is frenzied, and I think you’d probably want to be out of there by then. So now you have a bunch of ways to get to/from Epcot to MK.
If fireworks at MK are essential, disregard my advice entirely! The trip back to any non-MK resort at park close can seem ENDLESS.
Use the pools. Not just Stormalong, either. YC/BC has some really nice quiet pools to switch things up. Remember just how easy it is to walk to Epcot and back - there is a side entrance/exit to the Beach Club which takes you mere steps, probably 3 minutes, from the International Gateway Entrance. It is near room 1501 - just follow the signs to room 1501 from the lobby!
As for Florida in August, a few items make all the difference. Have a good, packable raincoat that you can don and remove quickly. I keep a pair of flip flops dangling from my backpack - wet shoes are a day ender, so when the rain comes, I bag my sneakers until the worst passes. A PakTowel is a nice bit of relief, too.