I second the Epcot Resort Area, which I guess would now

Include at least the Riviera.

For 8 and 9 year olds (or honestly 10-70 year olds) the pool at Yacht and Beach cant be beat.

I also agree that as DL regulars, you wont spend as much time at MK as you think. maybe 2 out of 7 days, but I would spend at least the same at Epcot, and 1-2 days at AK. Nothing is close to AK, but you can get close to Epcot (and Hollywood Studios, but again, pretty similar to DCA except for MMRR and Toy Story Land.)

If you want to do Monorail Line, I would rank GF last. It is a bucket list hotel, but lacks the convenience of the Contemporary and the ambience of the Poly. It's like Trader Sams, but everywhere. Like the Grand out here, it felt to me like your were paying for the lobby, which anyone can enjoy (except for the the holidays, which is why I'm staying there now and just had a cookie shot).

I liked the Wilderness Lodge and thought the water taxis were as good as the monorail (which break down way too often), but the theming is very close to the Grand, so if you stay here a bunch, it wont be as special.