So how will they use old footage of Carrie Fisher

There can't be that much footage, so the best thing to do is to use her scenes as flashbacks. I wouldn't expect them to be doing heavy CGI work to make an important scene like Leia hugging Ben or Lando or something along those lines.
The technology to make something like that seem convincing is almost there, but not quite yet.

 

I can see them using CGI to change her wardrobe possibly for some footage and also using voice over so they can to have dialogue that works for the new scenes. They may also use CGI to alter the background in scenes she was in so they make sense in the new movie (I heard there are a few scenes of her on D'Qar, but clearly they can't use that footage given what the FO did to that base in the beginning of TLJ. I don't think they will do any CGI on her that would change her physical appearance (hair, face, etc...) just because I think that would still rub people the wrong way since they may see it as a betrayal of the idea that they won't use CGI on Carrie. No matter what they do, I think it will be handled amazingly because everybody involved will want to do everything in their power to respect Carrie and the iconic character she is in the Star Wars universe.

 

There is an unseen scene of Leia giving a speech to the Republic. This could easily be re-used for the present time.

I hope you're wrong. We need to see Leia embracing her son. It's also not that difficult to do so. Even YouTube Video Edits make stuff like this happen.

 

Well, if they can do it - then I'm all for it. We don't really know what footage they have.

 

Who knows with the latest technology what they can do with those scenes. Just hope it fits the narrative and Carrie/Leia is given a proper send off.

 

if they are going to use unseen footage and get her into the movie.. then they should do what it takes to give her a meaningful role.
throwing in whatever they have for the sake of getting her on screen - i don't personally want.

they are a creative bunch - go for it JJ

 

they have back-tracked on that since and said they are using some unseen TLJ footage too i believe

 

I agree with @NinjaRen that we'll probably see Leia's Hosnian scenes repurposed for her gathering allies elsewhere. Maybe even Coruscant, if it hasn't been taken yet! After all, I'm sure there were enough green screens around to put her wherever they want.

Not sure what could've been used from The Last Jedi, though. Looking through cut concepts, but I don't see much about Leia.

 

Using the footage as flashbacks would be a tasteful application I think. LFL said they weren’t going to construct a CG reproduction of her for EPIX. The more tweaking you do with her likeness, for me, the closer you get to that point of disrespect. I say stay as true to her actual performance as possible. She was a person, not a prop.

 

True- I think it depends on what changes are made.

If Leia went to Hosnian Prime to gather forces for the Resistance in TFA, reusing that as her gathering forces for the Resistance in IX seems close enough.

But if we get some poorly dubbed frankenstein attempt at stitching together shots for the sake of an attempt at closure- oh yeah, that'd be real bad.

 

That’s a very good point. Retaining the core of the performance while making slight alterations to make it relevant to the current storyline. I know I wouldn't be unhappy with something like that.

 

My thinking is that they wouldn’t be doing this if they didn’t feel confident they could do it well. I’m not sure how exactly they’ll do it—solely using flashbacks seems possible, but I would like to see some footage of her in the present. Thanks to The Last Jedi novelization and some of the more recent Poe Dameron comics, we know that, in the time immediately following The Last Jedi, Leia’s health is declining and her death may be imminent.

But JJ also stated his confidence in being to bring some closure to her story, which leads me to believe we’re getting some present day scenes with her. I know there’s scenes of her addressing the threat of the First Order to the Republic and her receiving Luke’s lightsaber from Maz that were cut from The Force Awakens, and I also know it’s rumored that some of the shooting for Episode IX will take place where they shot the Yavin scenes for Rogue One. (The Resistance base on D’Qar heavily resembled the Rebel base on Yavin IV, so I suppose it’s possible they return to Yavin IV or a similar-looking planet to set up a new base.)

We also know that Maz is returning, so if she has something to do with the Skywalker lightsaber getting fixed in the next one, perhaps she presents it to Leia?

I don’t know. I would really love for Leia to have an interaction with Ben more than anything else, but considering that Han’s relationship with Ben was clearly one of the focal points of The Force Awakens, it seems highly unlikely that it’ll happen if they decide to kill Leia off. I have been a firm believer for a long time that Leia was going to be crucial in redeeming Ben. I’d give anything for her to be able to see her son return before she dies, but I think Leia’s death at the hands of the First Order could also be the last straw that ultimately brings Kylo back to the light.

There are a lot of options and it all depends on how much unused footage they have. The fact that they have enough to even announce she’ll be in it makes me optimistic, because I genuinely did not think we would get to see her in Episode IX at all. Whatever they have her do, though, I’m sure it’ll be amazing.

 

I don't think it will be used as a flashback.

First, in episodes 1-8, I believe there is a total of only one flashback, and while it was admittedly done on JJ's watch, is a very unusual and mysterious one. Ordinary flashbacks just aren't generally a part of Star Wars.

Second, the whole point of using archive footage was supposedly to bring Leia's presence into the events of episode IX. If they were just going to have Leia already be dead at the start of IX, in my opinion there is no reason to even use the archive footage.

 

Three. The second one is a brief dream in Rogue One and the last one is in The Last Jedi with the night Luke Skywalker failed.

 

I wish they would just change TLJ and make it an intermediate story and not part of the ST. Or make it a dream sequence of Luke seeing a possible outcome of choices as he see Ray approaching him on the hill.... You know, like it all never happened.. One can wish. ;-)