Well, Lucasfilm has made an official statement to squash this particular rumor.
Quote:
We don’t normally respond to fan or press speculation, but there is a rumor circulating that we would like to address. We want to assure our fans that Lucasfilm has no plans to digitally recreate Carrie Fisher’s performance as Princess or General Leia Organa.
Carrie Fisher was, is, and always will be a part of the Lucasfilm family. She was our princess, our general, and more importantly, our friend. We are still hurting from her loss. We cherish her memory and legacy as Princess Leia, and will always strive to honor everything she gave to Star Wars.
http://www.starwars.com/news/a-statemen ... new-rumors (the above is all that's on that link, to save a click)
I think it feels too soon for something like that to be done here, but have no problem with the practice in cases like Rogue One, and even Furious 7, where they wanted to do something special for Paul Walker, who had been in most of the movie already and died before it was finished.