Love all these guys but it's a flawed concept. A real AD wouldn't need and absolutely wouldn't want a "Football GM".
I think Zo is in the mindset of an NFL team structure with a GM, President of Football Operations, etc. I don't think that translates at all to a whole college athletics department. The "Football GM" could exist as an Associate AD but there would still need to be the hierarchy where the actual AD is above him on the organizational flow chart. Otherwise who would the "Football GM" answer to? Random boosters? Frenk? Football alum?