Thanks for posting the info regarding your league.
I'd still keep Evander Kane over any of those D. As far as ranking them, I would go:
I think MDZ and OEL have similar upside, but I give MDZ the slight edge because of the team he plays on. He should produce the same points, much better +/-and more Hits. You can probably get him cheaper than OEL as well as the consensus seems to be that OEL is the much more valued asset.
I'd be trying to sell high on Jordan Staal and see if that would snag you either of OEL or MDZ. You have enough good C that replacing J. Staal in the faceoff circle shouldn't be that difficult.
I'd also be tempted to trade Toews for Weber if you could sell this to the other GM, again, mostly based on the peripherals that Weber brings to the table.
Another asset you might want to consider trading might be Duchene. I still think he pans out to be a very good scoring C, but I don't see him contributing in PIMs or Hits.
For me to trade Kane, I'd be looking for a lot more than the D mentioned here. If I was a buyer of Kane, and I would be, I would be happy to give up MDZ or OEL to acquire him.