I: He is not to be confused with Gregg Williams
While their names are nearly identical, Greg Williams is much different than Gregg Williams, and the easiest way to distinguish between the two is that Greg Williams never coached for the New Orleans Saints, while Gregg Williams will forever be tied to the New Orleans Saints and Bountygate. If you don't recognize that event, Gregg Williams was hired on by the Rams in 2012, but that was hard halted due to his involvement in the New Orleans Saints paying bounties to players to take out opposing players.
Gregg Williams was reinstated by the NFL in 2013, and eventually did hire on with the Rams to serve as Defensive Coordinator under HC Jeff Fisher from 2014-2016. His latest role was defensive coordinator for the D.C. Defenders, an XFL team.
II: He coached under former Rams LB Coach Joe Barry
While some had speculated that the Packers release of DC Joe Barry may have paved the way for his return to the team's coaching staff, Greg Williams can accomplish nearly the same thing. Williams has 15 years of diverse NFL coaching experience, and has worked with both linebackers and defensive backs over that span of time.
While he joined Barry on the Packers coaching staff for one season, he certainly had enough time to glean some insight and defensive philosophy from Barry. Perhaps that is why he is on the shortlist for interviews. After all, if you wanted a younger version of Joe Barry, he checks that box instantly. After all, he was Barry's Assistant Linebacker Coach with the San Diego Chargers (2012-2014).