For defense the only guy that is available that I would take would be Streit and he won't come here. I would take Bartley on the 2nd pair over everyone else. A trade may work.
For Vanek, we would have to do something like Bourque, Watson, Ellis and 1st next year if we didn't want to give up a Wilson, Forsberg or our 1st. A deal like that would kill our depth. I would kick the tires because maybe Buffalo thinks Kostitsyn and Smith are 70 point players in their system, but it would be difficult to get Vanek.
For UFAs, maybe try for Bozak or Filppula though them at 5m is laughable so we need to get them cheaper. One of Chicagos two forwards, either Bickell or Stalberg might be available and would work. That is about it.
Horton is another Lombardi situation waiting to happen so I would pass there. Everyone else would not be a good fit or likely will sign elsewhere.