Thanks Pez, that's really helpful. I wasn't certain about the GF. Thought it might be a little too much for them (perfect for me though, lol). Going to stay in Sugarloaf next month so I'll check out the pool - from afar, brrr,I haven't stayed CL yet, but in terms of resorts, I'd definitely do BC since you said the girls love swimming and BC has the best pool. Especially for that age I'm sure they'll really enjoy the whole lazy river aspect of it.
I'd do GF for the second part of the stay. I loved AKL when we stayed there, we had a SV and I loved seeing the animals everyday, but being on the monorail is soooo convenient. Especially if you have ADR's to get to. The pool at the GF is much better than the AKL (Jambo) pool. The slide is much longer and more fun, I found the slide at AKL to be more like a kiddie slide.
You could also do have high tea at the Gardenview Room which might be a fun afternoon activity for the girls.

We did tea (their first) at the Grand last time and although I think they'll stick to juice/hot cocoa this time (NOT tea girls yet, lol) they did enjoy the experience.
Btw, we're really in table service as a family so I'm hunkering down on this snow day and digging into your TR... great reading do far.