Nathan Fillion for Carth Onasi.
Ron Glass (Shepherd Book) or Keith David (The Arbiter from Halo) for Jolee Bindo.
Nick Chinlund (from Chronicles of Riddick and Ultraviolet) for Canderous Ordo.
A young Julie Newmar for Juhani, just because she does that Catwoman voice sooooooo well.
For Saul Karath, with that uniform and hat, Robert Shaw (Quint from Jaws) comes to mind because of his good portrayal of that German tank commander in The Battle of the Buldge, back in the day.
http://www.robertshaw-forallseasons.com/On%20Set%20Of%20Battle%20Of%20The%20Bulge%202wm.jpg
He just has that vicious mean look about him in that movie.
Probably Yul Brynner as Darth Malak, because he has that piercing gaze he'd need to have, since Malak has that He-Man character Trapjaw device on his head, so all you'd see of his face was above his nose.
Harvey Keitel (Winston Wolf from Pulp Fiction) could play Colo Nord, since he has that short guy bad-ass attitude.
Mission Vao is kind of hard to cast for. Someone young with that kind of strong but carefree attitude, with some street smarts. Milla Jovovich kind of comes to mind. I can see her with head tails. Maybe Naomi Watts. Actually, thinking about it more, you want more of that innocence thing going for her, so I'm thinking someone more like Rose from Doctor Who. What's her name? Billie Piper!! That's it. She could do a good Mission Vao.
HK-47 is HK-47. Can't take away from that. He'd have to be computer generated and keep that same voice. That was perfect. (Die Meatbag!!)
Jack Black could play Zaalbar, because he's already big and hairy and grunts alot. HAHAHAHA.
Hugo Weaving (Agent Smith, Elrond) could play Revan, because after watching him play Agent V, in V for Vendetta, he can definitely do that kind of acting behind a mask where you never get to see his face.
And last, but not least. This little guy (V.I.N.C.E.N.T.) to play T3-M4 (when I first saw the design for the R2 units in the game, this dude came straight to mind because of his head shape).