Okay, while I was getting into the thick of reading this, a construction vehicle down the street started emitting a strange blip sound that was a spot-on match for the Alien motion sensors. And it genuinely made my heart speed up for a second. Combine that with your generator prompt being such a strong platform for this concept, and I'd say reality is conspiring on Ankheg's behalf.
This is both a fun original adventure and a great adaptation of Alien! It's well thought out within the fantasy world context, with plenty of new ideas to intrigue and shock the players. Plus I like how the Warrior evokes the original singular Alien, while the Nymphs evoke the hoards of aliens from sequels. You had your brain-cake and ate it, too! Nice horror, nice homage, and above all nice original spin!