I for one don't like letting Brown go. Miami needs to keep him, we dont need to sign Bush or D. Willams when we still have Brown and R. Williams. Yea, they had a bad year last year, but with health and solid O line these 2 guys are the best 1-2 punch in the NFL.
QB should be #1 priority, most people dont like Young, but the guy is a winner. He may not throw 300 yards a game, but he wins. Just don't abuse him like Jeff fisher did and he will perform. I think Young would work well with Miami.
Kyle Orton would be a gamble, he reminds me of Henne, throws a lot, but we still loose the game.
Mcnabb is past his prime.
Hasselback would be a nice fit, if he can escape Seattle.
Defense seems very solid. Last year they were very underated. The only thing you might want to add is more depth at safety.
O line could use more depth as well. As Miami has seen the last several years, you loose your starter and your screwed if the backup isnt even half of the starter.