NFL Connections #68, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
Modern linebackers
Bobby Wagner, Luke Kuechly, Fred Warner, Roquan Smith
Pass-rushing linebackers
Lawrence Taylor, Derrick Thomas, Von Miller, Khalil Mack
Middle-linebacker legends
Dick Butkus, Ray Lewis, Mike Singletary, Junior Seau
Steelers linebackers
Jack Lambert, Jack Ham, James Harrison, T.J. Watt