Marrone was in GA even before the ACC move. I'm sure the ACC move is one of the reasons Pitt is going for it. Pitt also has a new coach though, I'm not sure what kind of ties he has.
Just looking at Chryst it looks like not much.
Chryst Coaching Chronology
Collegiate
West Virginia (1989-90), graduate assistant
UW-Platteville (1993), offensive coordinator & quarterbacks
Illinois State (1995), offensive coordinator & quarterbacks
Oregon State (1997-98), offensive coordinator & quarterbacks
Wisconsin (2002), tight ends
Oregon State (2003-04), offensive coordinator & quarterbacks
Wisconsin (2005), co-offensive coordinator & tight ends
Wisconsin (2006-11), offensive coordinator & quarterbacks
Pittsburgh (2012), head coach
Professional
San Antonio Riders (1991-92), wide receivers, running backs, tight ends (World League of American Football)
Ottawa Rough Riders (1994), quarterbacks (Canadian Football League)
Saskatchewan Roughriders (1996), offensive coordinator & quarterbacks (Canadian Football League)
San Diego Chargers (1999-2001), tight ends (National Football League)