The 6-foot-5, 240-pound Mingo recently was rated as the No. 5 overall draft prospect by Scouts, Inc. and as the second-best junior defensive end by ESPN's NFL draft Insider Mel Kiper Jr.
The 6-foot-4, 245-pound Montgomery, a defensive end, was ranked 18th overall by Scouts, Inc., while Logan was rated by Kiper as the fifth-best defensive tackle among juniors.
Mingo, Montgomery and Logan join a mass exodus of draft-eligible juniors from LSU, which also will lose safety Eric Reid, linebacker Kevin Minter, cornerback Tharold Simon and running back Spencer Ware.
Ford, also a junior, tallied 1,394 rushing yards and 13 touchdowns in his LSU career.
Information from ESPN's Joe Schad and GeauxTigerNation's Gary Laney was used in this report.