I think before you entertain trading a player like Marner or Nylander. Players like Johnsson, Hyman, and Kapanen need to be peddled to create some cap space and better the team.
Players like Timashov, Micheyev, Agostino, Aberg, heck even Petan can provide what Johnsson and Kapanen do at a fraction of the price. Place those players with stars like Tavares, Marner, Matthews and Nylander see what they do.
Getting rid of Hyman, Kapanen and Johnsson can free up 7-10 million in cap space. Throw someone in like Ceci in one of the trades for an upgrade on D at a cheaper contract, you can free up even more.
The players I mentioned are expendable. I will argue that Hyman is probably the only one I would be hesitant to move because of the intangibles he brings to each and every game. But Johnsson and Kapanen are expendable.