Kinda odd they didn't show Lea's keyblade concept art yet. We don't know how the keychain looks like, are they doing that in purpose?
Regarding Isa, irregardless if an intended change or not, I wonder why from all the possible ways, do it in that book. Is the director trying to hint Isa got norted shortly after BBS events? I have no right to say this as I'm no expert in eagle eying but according some character in the games, Radiant Garden was gone 9 years ago. That makes the time between Ansem picked Xehanort and the six apprentices becoming nobodies and heartless was merely one year. Could be Isa and Lea perished as well shortly after them? We know now both of them lost their hearts in the same laboratory as the others, and as that lab disappeared among the world to become Hollow Bastian, wouldn't make such sense if was after that. Of course the details how Isa became norted and even how got that mysterious rage-meter scar remain an enigma, but putting together the little pieces, I would really say Lea and Isa became Axel and Saix as teenagers. Plus somewhere confirmed they joined the organization in the same day, so they perished together almost at the same time.