How Much Power Does ZT Have?

[THE PISTONS]

Every move that's made, I see some people say 'Trust ZT':

But, apparently Marvin Lewis didn't even get to decide who was active on gameday until 2011! Yeah that's really hard to believe isn't it?

'I bet you didn’t know that until 2011, Marvin Lewis didn’t even get to pick who would be active on gameday! If you don’t believe me, read this.' (This quote was from thegruelingtruth.com.)
https://www.cincyjungle.com/2011/1/5/1916318/mike-brown-press-conference-with-marvin-lewis-didnt-win-any-fans

https://thegruelingtruth.com/football/nfl/mike-brown-is-making-fools-out-of-cincinnati-bengals-fans-and-the-city-of-cincinnati/

So how much power would MB give a coach who was a QB coach last year and an Assistant WR Coach the year before?