NOPE. The facts don't line up with your theory.
The first three Spencer movies aired between July 22, 1993 and Dec. 1, 1994. The first episode of DS9 aired Jan. 3rd, 1993. So Avery Brooks had no problem being baby face Sisko in one show and bad ass Hawk in another at the same time.
The last Spencer movie with Brooks aired Jan. 4, 1995 which a full eight months before Way of the Warrior, which is the first time Avery went bald on DS9.
Plus, Ira Behr was the actual showrunner for DS9 and the guy he is talking to was the chairman for Paramount at the time the show aired. So forgive me if I take their word over yours.