These things are usually arranged by writing to the actor's agent and promising large amounts of cash.
Actors occasionally do agree to interviews, but most won't accept work unless they are under contract to do it, and that means going through the agent.
While it would probably be fascinating to hear the actor's opinion of the various characters he's voiced, I don't know whether they really know all that much about the roles they accept. Guy gets a stack of lines to read into a microphone. There are VA notes to give some clue about how the lines should be read, but there isn't any context. If the guy ever hears how it all fits together, it will be because he has played the game.