I like the idea of trading for Zaitsev. He plays big, and is defensively reliable. Not a star by any means, but would be an upgrade over Biega. I think that Zaitsev would be a big factor in Tryamkin wanting to return to Vancouver too.
Toronto will not want to sweeten the deal to move Zaitsev. Once Marleau is gone, so is they're cap concerns.
Toronto was already weak at RD, and if they move Zaitsev they will be even weaker. Their asking price will be for a RD.
I would bet the asking price for Zaitsev would be Stecher.... Which should be a hard NO from Van. I don't actually see much of a compromise deal here either.
A Zaitsev trade is probably better suited to another team like Carolina.