In a rare official statement on those rumors, Lucasfilm posted the following on the Star Wars website:
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.
We probably won't know this decade what was scripted for this Leia-centric movie, but here's why it won't happen, along with apnea as the official cause of death:
Fisher’s toxicology review found evidence of cocaine, methadone, MDMA (better known as ecstasy), alcohol and opiates. The test results “suggests there was an exposure to heroin, but that the dose and time of exposure cannot be pinpointed.”
You can read the 24 page report. Should have spotted the clue in Bright Lights when she was getting in shape for Force Awakens and sneaking some Coke.
An executive: "During the making of Jurassic World, he focused a great deal of his creative energies on asserting his opinion. But because he had been personally hired by Spielberg, nobody could say, 'You’re fired.' Once that film went through the roof and he chose to do Henry, [Trevorrow] was unbearable. He had an egotistical point of view — and he was always asserting that. When the reviews for Book of Henry came out, there was immediately conjecture that Kathy was going to dump him because they weren’t thrilled with working with him anyway. He’s a difficult guy. He’s really, really, really confident. Let’s call it that."
A veteran movie producer: "There’s one gatekeeper when it comes to Star Wars and it’s Kathleen Kennedy. If you rub Kathleen Kennedy the wrong way — in any way — you’re out. You’re done. A lot of these young, new directors want to come in and say, ‘I want to do this. I want to do that.’ A lot of these guys — Lord and Miller, Colin Trevorrow — got very rich, very fast and believed a lot of their own hype. And they don’t want to play by the rules. They want to do **** differently. And Kathleen Kennedy isn’t going to **** around with that."