Re: Who's voice do you hear the characters in?
There's a moment in Return of the Jedi where where Luke, prisoner on the Emperor's ship, glances briefly at the lightsaber they took away from him, and the Emperor notices. "You want this?" he says, in a mocking and amused voice that lets you know that, although his sense of humor is twisted and evil, he still has one. That is how I hear Xykon.
It should probably be noted that Xykon hears himself as James Earl Jones, or at least did in Start of Darkness. But I don't hear him that way. The only character I personally ever heard with anything like that kind of deep, resonant voice was Kubota.
Elan's goofy amiability always suggested a touch of Jim Henson in his voice to me, but just a touch. And whoever's doing the voice acting for Elan would have to drop that completely when he does Nale.
Thog sounds a lot like Strong Mad to me.