Im confused though. How did MX become young and whats this got to do with the Org and especially Isa? Also what happened to AX ?
Well he is in the realm of sleep and Sora and Riku are young there as well, so maybe that's why. I'm not sure what's going on with Isa, but it seems he's still working with MX. Of course this is entirely based off of the ending that's been posted, which has yet to be confirmed.