Well, it looks like we can confirm that the guy with the long hair and cane in the trailer is
From the Marvel.com interview with Guy Pearce (spoilers)
Spoiler!!! Click to Read!:
Guy Pearce: Killian is an interesting character as he’s somebody who came into this world with a number of physical disabilities. He’s never been able to accept those limitations though and has spent most of his life trying to overcome them in any way he can. His tenacity and blind determination in fighting for a better life are seen by some as irritating, as he often comes across as obnoxious. He just won’t accept the cards he was dealt, and being as intelligent as he is, has real drive to change and become a different person.
So we find him at the start of the film in a flashback and we see the ambitious, almost annoying, guy that he is. He takes opportunities to try and latch onto people like Tony Stark. So you see this very ambitious character and you see him later on in the film having made a change, and Tony and the other people that have met him early on kind of go, “How did this happen? How did he do this?” But he’s a dangerous character. He wants to become all-powerful. That’s sort of a driving force with him and Tony Stark realizes eventually what this guy is capable of.
Guy Pearce: When Killian started his organization A.I.M., however many years ago, Pepper was somebody whom he employed to work there. Obviously, from the outset he was very keen on her. She’s smart, she’s attractive, she’s a great girl. But Killian was someone that she was never interested in. When we meet Killian early on in the film, everything about him is unappealing on some kind of level and she always kept him at arm’s length. Then years later when he goes to her to basically look for funding and to get her involved again, she’s completely taken aback by how charming he is and how wonderful he now looks, plus his attitude’s changed. So she is kind of taken by him; she doesn’t quite know what’s happening to her and her reaction to him. And obviously, she and Tony Stark have a relationship, so this causes a little rift between those two.