Doughty for Marner would be amazing, even if we ended up signing Marner at $11m. We'd probably have to retain the max allowable on Doughty's contract for Toronto to even consider that, though, and likely throw in extra.
Fiala would be a great fit on Colorado who I think would welcome him. That said, trading Kempe, Laf, or Fiala should be a hard no unless the return is too good to pass up. Kempe and Laf, especially, should be forwards we build around.
Danault, Moore, Jeannot, Clarke and Spence are probably our best trade chips at the moment. They each bring something to the table that our roster needs, but at the same time we could absorb losing them without taking a step backwards. Hard to think that the return for any of these players makes us better, though, and losing Danault and/or Jeannot especially hurts our chances come playoff time.
At this point I don't see much trade deadline action for the Kings unless they either go all in (which would be a huge mistake) or finally start a legitimate rebuild around our future core.