Okay so I got a new theory here.
Keep in mind that this theory does rely on a good few assumptions.
- the Queen snuck aboard the drop ship along with a chest burster. (Chest burster was likely given birth to by Apone or Dietrich.)
- this chest burster managed to crawl and hide somewhere on the Sulaco.
- chest burster was either a queen in itself,
Or
- chest burster was a drone. We've seen drones capable of egg morphing. Now... what if in the absence of any hosts, a drone can go dormant or something, and then eventually generate an egg and pop it out? Is all it would take is the ability to generate just one egg, even if it kills the drone a short time later. I like my queen theory better since it would explain why it took so long to grow after popping out of apone or Dietrich. Assuming of course they were impregnated as soon as they were cocooned. I guess in the end it doesn't matter.
- so... once the crew was in hyper sleep, we can then easily have an egg, either through a queen or drone. Whichever Xeno it was can then take the egg and put it above the freezers. I assume a Xeno has the ability to telepathically tell an egg when to open. Xeno then crawls off somewhere, unable to join Ripley and the prisoners!
I suspect there will be some question as to why all of a sudden there were so many Queens being born? Could it be because the xenos were facing so much danger, and in such a situation their biology makes them produce more Queens?