First off,i'm waiting soo bad for this movie.But i'm going say somethings that you guys probaly don't know,or know,whatever.First off:
1-Xenomorphs are "probaly" not going to be in this movie,but something worst.
2-i think that i discovered who the hell they are,since i already writed about that in a another place i'm going make things shorter for me:
it clearly explains who were the Space Jockeys.In the Trailer you can clearly see an Humanoid figure controling the chair of the Space Jockey,i saw an amplied and a edited image too see more clearly.The head shape,isnt' human,also the Figure is of the size of the first movie chair,his eyes are black and he only have 4 fingers.If you read the comics,they clearly say that the Space Jockeys are Bio-mechanical and that 1 survived the Outbreak on their ship on the first movie,and he tried to terraform Earth.On the Trailer you can see a head of a Space Jockey being examined on a laboratory aboard the ship.Homever with no eyes like in the first movie.i don't see nothing that doesn't state that the Space Jockeys dind't created Booth humans and Xenomorph,and that they clearly are the race of "The Grays".That is said on the real life to abduct people and use Biological technology.
http://www.prometheusmovienews.com/wp-content/uploads/2011/12/jockey.jpg The figure in around 0:39 of the trailer.
http://ghostradio.files.wordpress.com/2010/06/alienspacejockey2.jpg You can clarly see by this official image,back from the collectors edition that this is a suit.
And here's the trailer: http://www.youtube.com/watch?v=sftuxbvGwiU
Also it's stated in the comics that the Space Jockeys have around 1.9 Bilion years.And that the planet as seen in the movies,is next to the same star sistem where the "abducted" says that is the "Gray homeworld" called the "Zeta 2 Reticuli system."While the star sistem where's located their homeworld " is just called "Zeta Reticuli Sistem" just next to the "Zeta 2 Reticuli System" on the Star map.

That would depend on which comic you are referring, and whether it is considered and accepted canon or not.

Some comic from the Dark Horse...can't remeber the name.But i'm going search.

Comic isn't as canon as the movies, so who knows now.

The Humanoid stuff and the Art of the Space Jockeys as also the "star stuff" are from the movies...Also isn't comics supposed to expand the universe?
Edit:i also find thishttp://www.avpgalaxy.net/forum/index.php?topic=41103.0 ....just rumors tough.But can confirm that the Plot of "aliens" is very conected to the Theory of the "Ancient Astronauts".

Not all extended materials are considered canon, Star Wars has an extended universe which George Lucas accepted them as official, but that didn't stop him from retconning the history however/whenever he wants. Bottomline is that as long as the creator of the whole lore says it's not official, it's not, extended materials can be moot even when it's accepted by the creator as official.

Here's the comic i was refering.I can't just remeber the name: http://cdn2.screenjunkies.com/wp-content/uploads/2011/12/space-jockey-101.jpg
Also i finded the edited image.You can clearly see that..this thing have 4 fingers: http://cdn2.screenjunkies.com/wp-content/uploads/2011/12/space-jockey-prometheus-trailer.jpg

Yeah, the comics are probably going to be invalidated by the movie. I'd rather they create a new story than be confined by the comics.

That can possible happen.Since the comics of "Gears of war" sometimes turned the "gatherd information of the series" into totally Nonsenseless.