The Louisiana native played in 11 games in two seasons, missing the last nine of 2017 because of a knee injury.
Lewis has nearly completed his initial group of Golden Flashes assistants.
The LB started 27 straight games for Hilltoppers, was named first-team, Al-Conference USA this season
Barrett will play for the Golden Flashes in 2018, have three years of eligibility remaining.
Moore, a former Louisville assistant, spent the past four seasons at Central Michigan.