Definitely don't stay at the loews Hotel, that's more geared toward universal.
Art of animation is a pretty cool hotel. We prefer the budget Disney hotels to the more expensive ones..
And the pools are really cool, teeming would probably be really cool for the 4 year old. The main pool has music playing under the water!
I recommend if you want to do the pandora area in animal Kingdom, try to be there as the sun goes down, there's lots of UV in the area and it all lights up so beautifully!
Make sure you do the evening closing events...they're so lovely!
I'd recommend starting your day early and going to park opening,
Pool or water park during the hottest hours of the day and heading into another park of the evening. It'll help you avoid some stress and tantrums!
Mickeys not so scary Halloween party- they run from Aug-oct 31st. I'd definitely recommend. We went in the Aug just gone with 1year old DS and DD, they have him a trick or treat bag, and he had the absolute best time!
Most things in magic Kingdom you'll be able to do with your youngest too...
Haunted mansion,
Aladdinds carpets,
Jungle cruise,
Pirates of the Caribbean,
Its a small world
Peter pan
Winnie the pooh.
Dumbo flying elephants,
The carousel of progress,
Buzz lightyear,
The people mover (off the top of my head!)
Also, it's off site, but if you like steak, Longhorns! I also recommend their chocolate stampede- it is FAB! Definitely a sharer though!
Also, we didn't get on with the niven 50s suncream this last trip, but banana boat spray on 100 factor was great. Especially on the little one.
Anyway you can stretch to two weeks? I think you might REALLY need it... especially with flying with two little ones!