NFL Connections #15, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
1985 Chicago Bears
Walter Payton, Jim McMahon, Mike Singletary, William Perry
Washington 'Hogs' era
Joe Theismann, John Riggins, Art Monk, Joe Gibbs
Los Angeles Raiders
Marcus Allen, Howie Long, Bo Jackson, Tim Brown
Dan Marino's Dolphins
Dan Marino, Mark Clayton, Mark Duper, Don Shula