It seems you cannot recruit a companion who have the same origin as you. Though not sure if it answers my other question like if you chose a origin you will start in a different location with the companion (same origin) or somewhere else?
Information I found is on this paragraph:
"When you're in character creation, you'll be able to select many characters, and actually all of these characters could be your main player character. They all have their own origin story. Even so, you will be able to freely chose your PC's origin, making him the double crossing thief, the heir, or somebody else entirely, based on all the origins coded into the game. You can even play somebody with no origin at all. You just won't be able to recruit a companion with the same origin as your main PC.
link:
http://www.rpgcodex.net/content.php?id=10045This is very interesting indeed, I can see why no RPG ever have done this and Larian just nailed it.
You also start with one character in the start of the game and others companions with their own origin can be recruited and just control them like you do on Co-op.