One bit of "extra" material that I am sure they are going to include is the attack on Dol-Guldur by the White Council (which should make for an entertaining, epic scene). If that's the case, then I'm pretty certain there will be at least a handful of "incidental" scenes in which the Council meets and plans their actions -- which would mean there ought to be a place for Galadriel as well as Elrond ad Gandalf. If so, I do wonder if they'll be able to get Christopher Lee to reprise Saruman. IIRC, Saruman didn't take part in the actual attack, but I believe he was consulted before hand.