I just watched IGNs rewind of the trailer where 2 of the editors talk about it and oh my god they say that the planet is lv426 and wonder how its going to become the barren wasteland it is in alien
Even that link that was posted mentions about the aliens being created in the film.
My theory is that they find the space jockeys. Something bad happens ect ect and they don't even encounter the aliens or maybe they see designs for it. I think the only thing tying the 2 films together will be the fact that the race that was piloting the derelict in alien is the same race they encounter in this film.
I don't think that they will go to LV426 or see the derelict. Well at least I hope not anyway
If this doesnt make much sense its because I have been up since 2am