I'd take Valimaki over any of the others by a pretty comfortable margin. I think he's got the most all-around upside. He can skate, he can move the puck, he can produce points, and he's also got the size and defensive side of things.
After that, it's tough. Maybe Brannstrom for the raw offensive upside. I still don't fully trust Liljegren's decisionmaking or Foote's skating. And Vaakanainen has always kinda struck me as the definition of "meh".
With the Canucks current state of defence prospects though, i'd happily take any of them. I'd just vastly prefer Valimaki. Could desperately use a guy with that sort of all-around upside in their organization.