Small point - The comnpany was named in Alien : "Weylan Yutani".
Ridley initially DID think of Weyland Yutani, but dropped the D as it was a little too on-the-nose a reference to the British company "British Leyland".
As for bug hunts and continuity; It's one of my pet peeves when post-Aliens entries to the franchise Change things without a valid in-universe reason.
The worst example of which is the timeline, and the company's knowledge of the Aliens.
First off, "xenomorph" is not a term specific to the Aliens we know and love. It's simply Gorman trying to look smart by using scientific terminology. It means "alien".
We just use it as a convenient term, is all. I mention this because I have seen some people interpret Gorman's briefing as his knowing what the Aliens are, and the squad being familiar with them too. This is not the case.
Furthermore, the entire point of Alien, Aliens, Alien3 and Alien : Resurrection was "If these things get back to Earth, we are screwed."
All of the tension, suspense and horror was based upon that core concept.
So when AvP came along, decided "Hey, we COULD tell the Ryushi story - Piece of piss, we'll go to Nevada, make some weird plants, dress up some cows as Rynth and hey! Nice cheap awesome action movie ahoy!... But no. We'll ramp up our budget by moving the story to Antarctica for no reason, and set it on earth in modern times.
...
What do you mean "Continuity"? Whgo cares about that?!"
Then Ridley himself made things even worse by giving everyone full knowledge of the Space Jockeys in Prometheus, and I won't even touch upon how badly he damaged his own ( co)creation with Covenant!
He himself said many times that the word "alien" in the title of the film is NOT purely a noun... The movie isn't called "The Alien", it's an adjective, it describes something that IS alien, in the sense that we cannot understand it.
Lovecraftian horror, eldritch terror, ALIEN.
... Nah, a wonky android was pissing about with a special chemistry set, and made some shit.. Things got a little out of hand.
To swerve back to what a "bug hunt" actually IS - and address the Arcturian issue;
I think we HAVE encountered lesser extraterrestrial lifeforms before, but nothing intelligent, and certainly no apex predators like the Aliens.
If we accept that the two universes ARE one, then it's likely there would be records of the Predator race somewhere, but I'd imagine that knowledge would be kept as hush hush as possible for as long as possible.
Arcturians - Well, we're hundreds of years into the future - Not long enough for human beings to show much /actual/ divergent evolution ( a la The Expanse ), but far-removed offworld colonists might show some adaptations to their environment over the course of a few generations.
It's also possible that Arcturus has a higher than average transgender population, and that humanity has as a whole gotten beyond the disgusting bigotry and transphobia we still see too often today - The grunts being facetious and sarcastic as they are, maybe that line was simply the equivalent of troops in Earth's far east seeking out "ladyboy" prostitutes for a bit of adventure