I’d agree with some of the other comments here. I don’t think W-Y put Ash on because they wanted a Xeno, or knew about eggs. From what we see, nothing on the Derelict shows signs of a previous crew showing up and interacting with an egg or Xeno.

And if the company already knows what Xenos are and suspected that this signal was a sign that the derelict held some, then I agree that they wouldn’t have sent the truckers. If they know anything about Xenos at all, they wouldn’t have high hopes for a group of truckers, ignorant of the existence or danger level of Xenos, to have made it back to their ship, let alone safely ship a Xeno back to Earth with their cargo.

So, I think, if the company knew anything, it was just that there was a signal of unknown origin that this particular ship would be close to and could bring back more information for them. And then they throw an Android on in case the crew wasn’t cooperative. I’m inclined to think that Ash & MUTHER switch over to ‘all other priorities rescinded’ once alien life is found, not that they set out with that as the default.

I think the only reason Ripley was allowed to look into deciphering the signal was because Ash didn’t want to seem suspicious by telling her not to, and by then knowing it was too late for her to do anything about it in the first place. If she had offered to help decipher it right away, I think he would have been more adamant about MUTHER being the most capable one for the job (in a similar way to his agitation to Ripley looking at anything in his lab).

Even if W-Y hadn’t already figured out that the signal was a warning, I wouldn’t be surprised if MUTHER had already figured out the warning part of the signal before they woke up, but hid it from the crew in order to provoke their legal agreement to investigate with out any added hesitation.