Suter would be a big loss given how thin we are at C, but he'd be a great option for any team looking to shore up their 3C spot for a couple of playoff runs. Namestnikov is having a career year thus far so who knows how long he sustains that, but of course he's definitely available. Gagner is like the perfect 13th forward but not much more beyond that, great dude and great teammate.
Yeah it would be dependent on how well Veleno is developing and how good/bad the team is doing. I'm a big Suter fan and he's actually been picking it up lately. But if the price is right and Yzerman doesn't think he's part of the future long term, then why not?
Namestnikov is a good energy guy, but not sure what his future would be on the team, though he could be a good 4th line/special teams guy for a while. At the same time, with his contract up, him having a good year and increasing his value, he could be the perfect trade piece for a team looking for a 3c/w.