.My point was 'Alien takes on characteristics of the host was a thing since they conceived the monster for the first film; not something made up for Alien 3'.I believe the full paragraph you were quoting goes as follows -- the second sentence giving the crucial context:
..FACT: There was much more to the Alien than met the eye. Since Ridley Scott used a painting by Giger as the basis for the adult Alien, he had to work backward to create the first two phases. During this process, the director came to understand the organism completely. "The nasty one," he says, "the thing that sprung out of the egg — the 'perambulatory penis' as we used to call it — is the father. All it does is plant the seed. And the next generation takes on characteristics of whatever form it landed on." This means that the ALIEN may not always be a biped! It could conceivably be a combination of the original Face Hugger and whatever host it uses!
So, the Alien is not made bipedal in the movie because it takes on characteristics from its host -- Sir Ridley muses that it might take on characteristics from its host because the Alien in the movie is bipedal.
Ergo, you can't really say that "the concept made it to the film and is shown on-screen", because it actually went the other way -- the concept is a rationalisation for what is on-screen, not the basis for it.
How they arrived at that point when making Alien is irrelevant.
Bust beg to differ, I'm afraid -- it is highly relevant. Sir Ridley retconning the inherited traits concept from Giger's bipedal design can't be said to make the concept relevant, because it isn't made apparent on-screen.
It is not until Alien3 that the concept is actually shown on-screen, in the creature's smaller stature, quadrupedal posture, and digitigrade hind legs.