[Disclaimer: As this is a 45 page thread I am unsure if I have already shared this thought some time ago, so apologies if this is a reiteration.. but hear it goes]
I think the Alien needed a female host to reproduce in the absence of an egg laying queen, and thus was curious about Lambert. It had tried to eggmorph Dallas and Brett.. For arguments sake, let's assume those were 'duds' /non viable eggs. It keys in on Lambert, it senses she is different.. But not *quite* what is needed... It "enters" and "explores" her insides to find she is missing what is required (ovaries) on account of her being transgender. This is why Ripley is not immediately attacked on the shuttle. She is too important.
Evidence to back this up throughout the series: In Alien 3, the superhugger attacks Newt first, though as she has not yet hit puberty, it moves on to Ripley. It doesn't attempt to impregnate Hicks despite him being a large strong individual. In Prometheus, black goo causes mutation in organisms, but in Shaw causes growth of what we can describe as a proto-hugger, and forms the basis of David's experiments. In Alien Covenant, Shaws ovaries are removed and used to create Ovomorphs. In H R Gigers original art showing the fate of the Jocky, the image is framed by his interpretation of Nuit, the Egyptian goddess of the night. From her stomach is where we see the eggs originating.
I put it forward that a viable eggmorph can only be achieved from a female host - a queen however can lay viable eggs.