The two voices are Steve Buscemi and Norm McDonald.
Dennis gaybert
Yes that is Gabrielle Dennis
Dennis Haysbert
Dennis James
Runway walk- xzibit
Dennis Farina, formerly of Law and Order. He made the commercial in early 2013 and died July 22, 2013.
Dennis does the main screaming vocals, but Shawn Milke and Shane Crump also perform screaming vocals.
Dennis Leary
Dennis Farina
Dennis Farina
Dennis Kline Grounds Keeper
Dennis Haysbert, according to wikipedia.