Why Montreal might not be a fit.
Cap space, so unless Columbus is taking Drouin (just what Torts needs), or Danault and Byron(Torts would love both, but Danault on his last year...)
Not trading Suzuki. This isn't PLD is worth him, or anything, this is a young centre growing with the team and looking better and better every game. While not drafted, he's kind of home grown.
Not trading Romanov. Bergevin spoke highly of him before he even joined the team.
Guhle likely not involved mainly because he was just drafted.
That leaves Danault is still there and maybe these last few games has given the team a new perspective on his value to them with Evans playing well and Suzuki playing well.
The best Montreal could do in that sense is Danault, Byron, 1st, Caufield and a prospect like Struble, Harris, Norlinder on D. If you don't compare them to the loss of Dubois, they're pieces I'm sure Columbus wouldn't mind to add aside from Byron, but as soon as you compare them to PLD, it's likely a huge pass.
In short, I would love to see the habs acquire PLD, but I think there's too much that needs to happen to make it work.
My other question is, if the Blue Jackets deal PLD for Laine and Roslovic, what does their centre depth look like ?