Progenitor (Xeno) Misdirection

I am wondering whether we have been misled in Prometheus over what the 'progenitor' to the xenomorph actually is. The creature in the end sequence is essentially stuck on the moon LV223. I know there have been speculation that the creature stows away on a spaceship or attacks a rescue party for Weyland. However, I feel that this creature is pure 'misdirection' and more of a homage to the Xenormorph. My interpretation is that the 'progenitor' is simply the worms that are more than likley primative life of the moon. The Engineers are attacked by these evolved species which have come in contact with the black biogoo. The creation the 'hammerpede' or 'cobrahugger' is by chance a deadly creature with acid for blood, which lays its young inside of it's victim. The engineers have already been attacked..... they're are holes in their heads and chests. The 'hammerpede' erupted from Millburns mouth. We did not see whether or not there was any creature that came from Millburn's chest; like the holes the Engineers have in their's..... The Engineer from Alien is fossilised. If we look at the time frame of Prometheus related to Alien then it is entirely plausible that the derelict escaped from LV223 after being infected by a 'hammerpede' and crash landed on LV426. The offsring of the Hammerpede chestbursts from the Engineer kills any remaining crew on the derelict and then either lays eggs or morphs the crew into eggs. Later the derelicict pilot is fossilised in the 2000+ years that goes by before the Nostromo discovery. I have ruled out the new creature because it didn't exhist when the derelict crashed on LV426. So it coulnd't of killed the Engineers on LV223. My questions are where are the eggs?? Where is the tunnel system of the xeno's?? Is it that they are larger due to the Engineers and the oxygen levels?? The temple could be their tunnel system and due to the lack of scientific study maybe we just didn't see where the nest and eggs were of the Xeno's?? There are so many ways that this could go........