Honestly, I feel it's obvious that Fox considers these franchises and every single installment - from
Alien (1979),
Aliens (1986),
Predator (1987),
Predator 2 (1990),
Alien 3 (1992),
Alien Resurrection (1997),
Alien vs. Predator (2004),
Aliens vs. Predator: Requiem (2007),
Predators (2010),
Prometheus (2012),
Alien: Covenant (2017), to
The Predator (2018) - to be canonical to each other, they simply act in a manner of continuity similar to the Marvel Cinematic Universe where there are crossovers and separate storylines but they all ultimately take place within the very same fictional (and profitable) universe.
It began with Dark Horse Comics first suggesting the concept of the shared universe in 1989 (and had been expanding upon it ever since), and Fox soon officially initiated the concept in 1990 with
Predator 2 and the famous Xenomorph skull in the Yautja trophy room, and attempted to produce a feature film throughout the following decade until it was officially cemented together with
Alien vs. Predator in 2004 and
Aliens vs. Predator: Requiem in 2007, and both films undeniably existing in continuity with both the
Alien and
Predator films as even openly expressed by the cast and crew behind the films (the directors in particular). Noting that
AVPR actually features a Space Jockey skull in the trophy room.
Then in the same vein as Marvel's
Iron Man 3, the 2010 release of
Predators continued on a separate storyline but still existed within the same continuity as all previous eight
Alien/Predator films and even featured several references to James Cameron's
Aliens from 1986 (as this film was intended to act as the
Predator-equivalent to Cameron's film) and included, as the director revealed, a Xenomorph lower jaw on the Berserker Predator's mask.
The shared universe would also be further expanded upon through various home video releases (such as
Alien/AVP/Predator - The Ultimate Annihilation: Nine Movie Collection), video games (notably
Aliens vs. Predator from 2010,
AVP: Evolution from 2013, and
Aliens vs. Pinball from 2016), comic books, novels, boardgames (such as
AVP: The Hunt Begins from 2015 and
AVP: Unleashed from 2017), and countless other merchandise and events, so Fox clearly has no interest in dissolving the shared universe anytime soon.
Then came Ridley Scott's two prequel films
Prometheus in 2012 and
Alien: Covenant in 2017 and divided the fanbase further and even though they technically take place within the same universe as the previous nine films (especially when no evident contradictions exists) we don't really speak about these. Although we have to note that the Fire and Stone (2014-2015) and Life and Death (2016-2017) comic books by Dark Horse Comics actually ties together the Alien, Predator, Alien vs. Predator, and Prometheus brands quite explicitly and again confirms continuity, and the events covered in these comics were even acknowledged in the popular
Alien: The Weyland-Yutani Report (2014-2016) in the "Company Time Line" section.
Also, to address the common claim that the company histories of Charles Bishop Weyland and Sir Peter Weyland supposedly contradicy each other, I'm going to say that is absolutely false, as there are no contradictions here whatsoever. Charles Weyland formed Weyland Industries sometime around the 1960's or 1970's whereas Peter Weyland was first born on October 1, 1990, and could thus easily be the son of Charles Weyland. Peter's father was after all unnamed and described as a self-taught engineer, which fits with Charles. Interestingly enough, Peter secured a patent for a synthetic trachea on October 1, 2004, and could potentially have cured Charles of his bronchogenic carcinoma (lung cancer), shortly before Charles was declared deceased on October 10, 2004, and it would take eight years before Peter became of age and founded the new Weyland Corporation in 2012, though still keeping the old Weyland Industries intact and the name featured on the corporate website and promotional material for instance.
Peter could simply be understood as having inherited his father's assets and bringing the company back into the spotlight and towards its interstellar destiny (along with Yutani Corporation and the Predator handgun acquired by Miss Yutani from Gunnison, Colorado, in 2004 which aided in the development of such advanced technologies as FTL drives, as according to the directors). Weyland Industries is also mentioned in a Sevastolink terminal in the 2014 video game
Alien: Isolation and Weyland Corporation is featured on the main meny of the 2013 video game
AVP: Evolution.
However I'm certainly not the first to suggest this. Alien Theory further elaborates on this;
https://www.youtube.com/watch?v=kkc4_9YIqI0Further addressing another common claim that the synthetic David supposedly created the Xenomorphs in
Alien: Covenant and thus setting up a supposed contradiction with the
AVP films featuring Xenomorphs on Earth in 2004, this is not actually made clear in the movie itself, but it leaves such an issue up to interpretation. However, this is cleared up in the official novelization by Alan Dean Foster (who not only wrote the first three
Alien novelizations but also wrote a tie-in novel to the film titled
Alien: Covenant - Origins), where David elaborates and states quite clearly that he did in fact NOT create the Xenomorphs, but the Engineers (Space Jockeys) actually did, and David merely used what they had already created, including the black goo pathogen and pre-existing Ovomorphs (that is Xenomorph eggs), to create his own variants of these star beasts or "perfect organisms".
Prometheus itself showed that Xenomorph-like creatures are very easily produced through the black goo, and this substance has seemingly existed for billions of years, giving more than enough time for Xenomorphs to be produced several times, and even if it were true that David was the ultimate creator of the Xenomorphs, you still could not rule out time travel (but we clearly don't need to go there).
Noting further that if the very existence of
AVP/AVPR and the
Predator films for that matter weren't enough to prove that David didn't create the Xenomorphs, then perhaps the home video release of
Prometheus would change your mind with its inclusion of Peter Weyland's log "Quite Eye" which quite clearly states that the company already detected the distress signal from the crashed Derelict ship (containing all those Ovomorphs) on LV-426 before the events of
Prometheus/Covenant (and it would be consistent with Captain Dallas' assessment of the Space Jockey pilot being fossilized and implied to be ancient). Even the now-defunct online MU/TH/UR 6000 interface on the Alien Universe website had classified information on such topics as Predators/Yautja.
Then of course came
The Predator in 2018 and further confirmed that the shared universe indeed still remains intact, with several references to
Alien vs. Predator from 2004 such as Lex's spear which the Scar Predator made out of a Xenomorph's tail, as well as references to the
Alien films such as the alternate endings which were approved, produced, and filmed featuring Ripley and Newt (which would seemingly suggest time travel technology and thus set up the arrival of Neill Blomkamp's
Alien 5 and allow for his film and
Alien 3 and
Alien Resurrection to exist simultaneously).
After all, Fox is sitting on a real goldmine with the shared universe (if only they could handle it better), and they may indeed still be interested in going forward with
AVP3 (as even Shane Black would suggest), especially now that they won't let Scott make any more
Alien films after his recent failures. Personally, I completely acknowledge the shared universe as canon (not to mention how silly, petty, and unnecessarily confusing it would be to suggest some films takes place in some alternate universe), and I'm very welcoming of continuing to expand this shared franchise, especially seeing as I grew up with it and still loves it to death. Anyway, we'll see where it all goes from here on under the new rule of Disney.
