Just to clear some things up:
Zeta 2 Reticuli is a star in the Zeta Reticuli system, not a planet. In Alien, Lambert said that the Nostromo was "just short" of Zeta 2 Reticuli, meaning that they weren't actually there yet. In the movie, there's an unnamed fictional ringed planet in this system, and LV-426 is a moon (or possibly a planetoid) of this planet.
So again, Zeta 2 Reticuli itself has nothing to do with the aliens or xenomorphs. It's not the big ringed planet and it's not LV-426. I think Scott is a little confused, but then again, it's been 30 years for him.