It sounds like Flores and the GM didn't get along at all and they were having a major power struggle. Last time that happened they choose the coach (Gase) instead of the GM and that was a disaster, so they went with the GM this time.
With Flores and Culley being fired, Tomlin is now the only black head coach in the league, though I would expect at least 1, if not several, of the openings to go a black head coach (Flores likely will get 1 and it sound like Bienemy may finally get his shot).