Terms of the deals were not disclosed.
All six of the team's draft picks this year are now under contract.
Benjamin, the 28th overall pick, had 84 receptions for 1,506 yards and 19 touchdowns in two seasons with Florida State, including the winning 2-yard TD catch in the Seminoles' BCS National Championship win over Auburn.
Turner, the 92nd pick, started 20 games and played in 25 during in two seasons at LSU. As a sophomore, Turner was a second-team All-Southeastern Conference selection, starting 13 games and leading the conference with 21 blocks resulting in touchdowns.