For me Canon has nothing to do with films, comics, books, etc.
I have my own idea of what I would have liked the canon to be and what I would have liked the authors had explored.
The Universe is inhabited by many sentient and non-sentient species, e.g., the Arcturians (Aliens)
Through space exploration, humanity has encountered some of them.
One of these species is the Alien that we all love and somewhere in the universe there is a planet which the Alien is native to. They are probably an ancient species, even million years old.
They are highly aggressive and dangerous—which is an euphemism—but they are not intelligent. One of the scenes I hate the most from all films is the one where they imply that the Aliens somehow managed to turn the lights off in Aliens. I could accept it if they destroyed a source of light but not that they turn off a power generator.
An intelligent animal attacks with plans, evaluates risks and gains, does not rush towards its death only "because"—unless driven by some fanaticism or fear of a worse punition (i.e., soldiers sent to their death for religious or military reasons).
As they say on Earth, which came first? The egg or the chicken? The Aliens reproduce through the eggs, only laid by a different type of Alien that we all know as the Alien Queen. No other types of "Aliens" exist. There could be slight variations if the Alien is born from different creatures, that is, non-human, and whether this makes sense or not from a scientific point of view, I don't care.
—Eggs are only laid by Alien queens
Another species is that of the Space Jockey, which for some reason (scientific, military, etc) were transporting alien eggs in their ship (Alien).
Corollary: The Engineers do not exist. Prometheus, Covenant, AvP and AvP2 did not happen.
—No alien species has ever been to Earth (I do hope they will though, in fiction).
