Prometheus in an Alien Universe

The Alien “born” at the end of the Prometheus film does not necessarily explain the beginning of the Xeno (Alien) race, but rather an other lineage beginning of with the same ancestry. Remember, the race of Engineers, that created them, is an ancient race that has existed for far longer than their Earth "children". Many previous generations of Aliens could have been born and escaped LV-223 and traveled, via ships, to LV-425 (see Alien) and many other planets long before the Prometheus arrived…possibly 10′s of thousands of years or more before. This would give ample time for the Xeno-forms to evolve, through hosts of different species, to the creatures we experienced in the alien movies.
As to the the Aliens/Predator films, they would fit into this framework quite well. The Alien(s) escape LV-223 after killing almost all of their “creators” andspread throughout the galaxy as stowaways on various ships. At some point in time they get noticed by the Predators and are then captured and bred for sport (see AVP) on ancient earth and possibly other planets as well. Later, Weyland becomes aware of the fact that we are not alone and becomes obsessed with the Aliens and finding them. This prompts his lifelong endeavor to fund the research that leads to the events in both the Prometheus film and the Alien films as well.

In this vido it is easy to see that, while not the exact Alien we are used to seeing in the Alien franchise proper, it is significantly close enough to understand the familial connection and common lineage. Its basic body configuration and predominant elongated domed head are all too familiar. Furthermore, it has the distinct birthing maneuver of the Alien...that of exiting straight through the abdomen or chest cavity of it's host. This proto-Alien is definitively within the acid blooded creature's family tree and equally to be feared.

1. Engineers create Mankind on Earth as some sort of experiment or as part of a God complex. (step 2 could be step one without changing the basic flow)
2. Engineers create the Alien species on a distant planet at sometime in the distant past. (for God knows what reason)
3. Aliens escape after killing most of the Engineers in the distant past.
4. Aliens stowaway on ships leaving the world of their creation, facehug, stomach burst and kill as they spread throughout the galaxy. They evolve quickly as they pick up traits from their hosts.
5. Events of the Aliens vs. Predator films show the interaction between the Alien creatures and the Predator race and man's earliest encounters with each species. (earth's past).
6. Events of AVP/Predator films show the future interactions of all three species. (modern time)
7. Weyland Corp. gets involved through the events in AVP and research and exploration begin in the hopes of finding the Alien race and profiting from the discovery.
8. Prometheus explores LV-223 because of Weyland Corp. funding and finds not only the evidence of the Engineers, but also the birthplace of the Aliens.
9. Alien (1979) and the remaining Alien franchise continue the story.