But i think they said only one pred will be there throughout the whole film.

maybe there just weak aliens

they become Warriors eventually in the movie, as we see in the trialer. But i dont think the pred will have trouble with the new born drones.

I know what prbably gona happen the predator esily takes down the regular aliens but then he has to face the predalien

In the original AVP comics I believe the Predators brought Aliens around with them to populate on new worlds so that the Alien could be hosted by native species and then a hybrid Xenomorph hunt could begin. That demonstrates a level of control and superiority over the Aliens that humans had never successfully achieved.

How can the movie be unfair? The thing about Aliens is their numbers. When Wolf kills those two in his hand, there could be four right behind him. In AvP each alien was a little more personal than usual but in this movie it reminds me of Aliens (movie). Many aliens died in Aliens.. The Aliens basically won in AvP. All because of Anderson but thats besides the point.. Why not let the Predator have this one?