I don't think this alien can be related to the alien from Alien, at least not directly. The ship that crashed can't be the same one from Alien, because a) there's nobody in the suit, since the Engineer left it to go to the life pod, b) there was no big hollow complex beside the ship in Alien, c) Weyland (the company) knows exactly where this planet is, and that doesn't fit with what we see in Alien, and d) there's no reason the ship that crashed here would have a signal beacon going for the Nostromo to pick up.

Personally I think the ship we saw in Alien is the ship that Shaw took to go find the Engineers. It crashed somewhere, after doing whatever she does (which we will perhaps see in the sequel?), and that's what Weyland was secretly looking out for. Presumably the ship Shaw took would also have the weapons on it, and so in he right circumstances could also produce a xenomorph. And that might mean that Shaw (or a rebuilt David) was the one inside the suit in Alien.