Edwards, 21, was stabbed to death outside Richards on Richards nightclub. He died later in hospital.
The judge said Patrick Plowman, Sebastian Miazga and Nolan Swallow repeatedly punched Edwards in the head, then kicked and punched him after he was limp on the ground.
Plowman and Swallow were sentenced to seven years minus the time they've already served in custody.
Miazga was sentenced to five years in prison.