I don't know, his career isn't over yet, I guess that depends on how strict you are to determine ATG status
The Klitschko's? Their ATG'ness is debateable, but they were always considered heavy favourites in fights...
na, everyone starts off as an underdog sometime in their careers imo. even though tyson wasnt an underdog going into the spinks fight it was a pick em fight written all over it. nobody expected that fight to go down the way it did. roy jones jr was an underdog going against james toney and james toney was an underdog going against michael nunn. everyone starts off as an underdog