A close second though - Sargent Rusk. There is no reason why the Jedi Knight would take him aboard.
I'll second this. He's really the odd man out. An SIS agent would have probably fit in better with the jedi knight than a guy the higher ups obviously wanted to get rid of (really? Assigned to the Knight until the Sith Empire is defeated?).
I'm half and half on Doc. He's a moodmaker, but has no real place with the jedi knight aside from being a robin hood-esque doctor. Not to mention, any guy that thinks Kira is uptight is probably not in the spectrum that a JK would want to keep around.