Today, NA Square Enix (finally) updates the site... with three more characters; Cecil, Bartz, and Terra. Also note the name change from Butz to Bartz and from Tina to Terra. Nothing entirely new but at least it is something... sorta http://na.square-enix.com/dissidia/ Plus, I've found an interesting piece of info regarding the English Voice Overs. Grant George is credited under Dissidia as the Warrior of Light on his official site. You can also see more of his credits from shows, anime, video games, etc. to see if you are familiar with him (for all I know, he's the voice of Kilik from Soul Calibur). I hope that this will be a start to more revealing of some other English VO's in the future. http://www.dynamicduovo.com/aboutgrant.html
They changed Tina to Terra because Tina sounded too commonplace I believe. Butz was rightfully changed to Bartz because seriously, Butz? Butts? That's just cruel for an official name. ...lol, I'm suddenly reminded. In my first playthrough of FFV, I named Bartz "my ass". Little did I know how accurate that actually was to his real name.