Ridley Scott does as Ridley Scott pleases, I guess, and in a long interview with Filmophilia Scott revealed a few details about his plans for Prometheus, including that the tie-in to Alien might be a lot more vague than we expected. Here's what he had to say when asked directly if we would again see the xenomorph in the film:
No. Absolutely not. They squeezed it dry. He (the xenomorph) did very well. (He laughs) He survived, he’s now in Disneyland in Orlando, and no way am I going back there. How did he end up in Disneyland? I saw him in Disneyland, Jesus Christ!
(https://www.cinemablend.com/new/Ridley-Scott-Says-Xenomorph-Absolutely-Prometheus-28428.html)
The Great Movie Ride closed on August 13, 2017, becoming the last operating attraction from the park's opening day to close.
"Next, the ride vehicle continued into a darkened corridor of a seemingly abandoned spaceship, revealing itself to be the Nostromo, the doomed vessel from Alien. The ride vehicle passed an audio-animatronic Ellen Ripley (Sigourney Weaver) holding a flamethrower as she prepared to confront a creature lurking within the ship. Guests could also hear Jones, Ripley's pet cat, meowing in the darkness, as well as the Nostromo's "Mother" computer warning of an imminent ship self-destruction countdown. Hearing this, the gangster or the bandit became nervous and sped the ride vehicle through the ship, but not before the Alien appeared and attacked the guests, popping out from both the ceiling and the wall."



Would Ridley Scott work with Disney for a Disneyland version of Alien? I seriously doubt it.
"He survived, he’s now in Disneyland in Orlando, and no way am I going back there. How did he end up in Disneyland? I saw him in Disneyland, Jesus Christ!"