I think Joe would be too strong for Pavlik, and would win by UD maybe 116-112 or so. Like with Mayweather, there is a puzzle to beating Joe, which several fighters have found some of the pieces, but not managed all of them for the duration of the fight. I feel Joe is beatable, but not by Pavlik.
Calzaghe by stoppage late rounds ... Pavlik can't handle a fighter on his toes with fast hands. I think Calzaghe takes him in deep waters and drowns him.
Joe would win every round, before finishing him off late God created Kelly Pavlik to make Joe look good
It's very likely, although I think he should stay on to 50 fights, beat Marciano's record and then retire.