New scans have been released through VJump of Final Fantasy XIII, mainly concerning the newly revealed character, Oerba Yun Fang. She is seen in several screenshots displaying her role in battles, which is a clear confirmation that she will be playable character, as well as having Bahamut as a summon. Furthermore, there is also interaction between Oerba Yun Fang and Lightning, Oerba Dia Vanille and Sazh, which indicates she will also have a role with interacting with other main characters, as well as the storyline itself.

Apparently, Oerba Dia Vanille has an Australian voice actor, though it doesn't seem to come across as strong. As for Serah, I think in the end if she it a playable character she'll do a Rex in FFXII and you'll be able to control her for a little while, the she'll disappear after something happens to her, which again, can be seen in the trailer.