If the Dolphins win out there's a good chance they would be the 6th seed, but I think what you're saying is that if they make the playoffs their best chance is against the Steelers and I would agree with that. Unfortunately I think it's just as likely they lose 3 of their next 4 as I think @ Texans, vs 49'ers and @ Jets are all going to be tough games and Miami @ Cleveland is no gimme. Realistically Miami needs to win 3 of 4 and hope for some help from Denver and Indy for the 7th seed, it's possible but not very likely. I still think their chances of making the playoffs hover around 5% and their chances of winning a playoff game are < 1%, but I'd still like to see them make the playoffs anyway. One more game to watch this year.
The Dolphins have to move ahead of either the Chargers or Broncos for a playoff spot, so those are the two teams to root for losing; based on the remaining schedule Miami is unlikely to pass the Chargers.. The Ravens quite possibly could move ahead of the Steelers to win that division.
The Steelers have an incredibly tough remaining schedule, they could go 0-4. They play the Eagles, Ravens, Chiefs (short week), and the Bengals.
The Bronco's have Indy, Chargers, Bengals, and Chiefs, the Bronco's & Chargers are battling for 2nd in the division behind the Chiefs who have locked up the top spot.
The Chargers play Bucs, Broncos, Patriots and Raiders, a few soft teams.
The Colts have one of the easier remaining schedules with the Bronco's, Titans, Giants, and Jags, so with the exception of the Broncos Miami wants Indy to lose at least one of the other games.