Yes, Mr. Judge does the voices of both Beavis and Butthead. As for the others, I couldn't say.
He lives here in Austin and sends all the stuff up to New York. He has an office in the same building with the people who did "Slacker".
He's been seen around town numerous times. One time he tried to get into a club without paying by telling the doorman who he was. It didn't work.
Rock on!