Your very welcome for this info Mike!
I was so excited about this I just had to say!

This is good news. It's atleast telling me the collection of voice actors are starting to wrap up with their work.

Hmm... now it'll be interesting what voice actor Master Xehanort will have, since the Nobody voice actors are reprising the role for their Somebodies.
If it's Richard Epcar (Xemnas), then that'll be an interesting sign.

Awesome. But if they're children, are they going to edit the voices with a program, or have the actors change their own voices...

Confuzzled..

I really can't imagine Master Xehenort with Xemnas' deep voice.

I know Flynn (Axel) has done younger voices before so he should be fine, unfortunately I don't know much of Thorton's work.
I believe that VA's have to have the skills and abilities to do a wide range of voices, otherwise they wouldn't be able to afford the food they put on the table. Voice altering is unlikely, but still possible.

I'ts really just a long shot. If the Japanese VA for Xemnas was the same as MX, it would have been mentioned or used as proof in some wild theory about the game, so it's really unlikely.
It's even harder to imagine Billy Zane doing the voice...

Quinton Flynn ALWAYS play Axel in Kingdom Hearts. (North America version)