Spoiler cast announced http://starwars.com/news/star-wars-episode-7-cast-announced.html http://www.avclub.com/article/and-heres-your-official-star-wars-episode-vii-cast-203968
They should all be fine except for maybe Carrie Fisher. She looks terrible. Hard to imagine her making Leia play a big role in the film without a lot of work.
Perhaps after Lea's stint at Jaba's she opened her own bar called Wookies. Only way to work the look into the story.
With CGI, they can digitize/use Carrie Fisher's original Star Wars body, digitally age it, and then they will just use her voice acting.
Glad they are gonna use extended universe as they see fit. There are far too many Star Wars books. Just like comics, I'm cool with film universe/ book universe being different, although many of the nerds disagree.