"... In desperation, the Alliance launched five Sleeper ships..." - Ext. FL Intro
Now, this may very well be why they cut that part of the intro. Actually, they cut most of it. We can't go off of a video they didn't use, as the information would have likely been changed for more accurate in-game interpretation.
Quote: The Liberty Backstory says that there were indeed eight sleeper ships.
I'd lean toward this. Since they wrote the backstories after the game was made, and isn't another scrapped idea.
Also, judging by the fact that the Ext. Intro was scrapped material, Sol may very well still exist
--------------------------------------------
So, playing along with the idea that the extended intro information is accurate...
In relation to the dock its moored on, the General's ship is most definitely not a fighter. More likely a cruiser or battleship.
"Somebody had to warn the colonists about their true enemy! The Nomads!"
Implication: He went to warn them.
"We have grown, we have flourished, but we will never forget."
Implication: He successfully reached them and told the tale. Otherwise, how would he know that they flourished?
Oh, original thing... That is definitely the General's ship landing on Manhattan. And it is Manhattan, or... It wouldn't make much sense if it was another planet and it transitioned Manhattan over the Sleeper Ship building.
--------------------------------------------
Now, he says that by blind luck a young General, blah blah. Speaking in third person as we later find out because, "I knew then that I was spared for a reason..."
But then he proceeds to say, "That was 800 years ago. Since then we have grown..."
An 800 year old General... Right... Anyways, need I mention any other flaws in this plan? As cool of an intro it is, and as much as I admire it, it is pretty sketchy with the details.