Donahoe had full control over the decision making as president and GM when he was in Buffalo... He could have hired who he wanted..
He interviewed guys like Marvin Lewis and John Fox and passed them over for Gregg Williams.... Lewis has been HC for how many years now in Cincy? And just took a talented young team to the playoffs... Fox did the same in Carolina with several playoff bids and went to a SB... He's doing the same his first year in Denver...
After these interviews and Williams hiring, Marvin Lewis' agent had this to say: http://abcnews.go.com/Sports/story?id=99873&page=1#.Twt17Bxy9j4
Hmmmm... Lack of consistent dialogue or communication with Donahoe?? Sounds like a complaint he got from a lot of people while here... along with a heightened sense of arrogance and refusal to take any advisement from others under consideration... It was his way or the highway... And choosing Williams over Lewis or Fox showed that he felt he was the smartest man in the room and needed to prove it to the world.
As far as the Mularkey hiring, I'm still not sure if he would have been successful or not.. He seemed like a better hire than Williams.. But remember, Donahoe had a chance to hire Lovie Smith or Romeo Crennel too... We'll see if Crennel has success in KC, unlike Cleveland... But Lovie Smith, much like Fox, has had several playoff bids and a SB appearance in Chicago... Here's an article on Donahoe's options in 2004: http://www.usatoday.com/sports/football/nfl/bills/2004-01-07-coaching-search_x.htm
Also, Mularkey wanted Ken Whisenhunt (a great OC with Pit. which eventually got him the HC job in Arz.) as his OC... Donahoe overruled him and hired Tom Clements instead.
All in all, the way I see it, he passed over some great opportunities to hire eventual successful HCs (and assistants) for guys he felt would make him look brilliant, ala the Bill Cowher hiring, if they worked out... He outsmarted himself...
Here's one other good article on Donahoe's mistakes in Buffalo: http://www.buffalorumblings.com/2009/4/1/816875/seven-ways-donahoe-destroyed-the
You'll notice Mistake #1, 6 & 7 are exactly what I'm talking about..