I always wondered why they didn't just make a Aliens style film and chuck a Predator in to confuse the Marines to what is hunting them. Predators as shown in the vs Comics can adapt well to existing stories/universes. I think the AvP films tried to hard to connect the two species when we would have accepted an Alien film where the Predator is hunting Xenomorphs.
A Marine saying I think it's not after us or something along those lines would have been enough.
-TJ88