The only thing that is known so far is that two interviews were recently conducted. One of which, according to Mike Florio of Pro Football Talk, was with former Indianapolis and Detroit Lions coach Jim Caldwell. The other, reported by Tom Silverstein of the Milwaukee Journal Sentinel, was with former Colts coach Chuck Pagano.
NFL regulations state that teams can't interview coaches of other teams during the season or if said team has a spot in the playoffs. Once the season ends and the playoff seeding is fully determined, however, everyone is fair game.