This is why trading Dermott has been and is a terrible idea

No they're not. Someone else gets injured, Liljegren gets called up first. & what team isn't on the verge of calling up an AHL option after 2 injuries to their defence? Remember that Sandin is out too so under normal circumstances he'd be called up well before Marincin. They've been hit by multiple injuries, relax. It happens to every team

If that's the case they should call up Liljegren and play him

If a righty goes down sure, or I suppose you move Brodie to the left side and give Liljegren some time. I am just not sure what I trust less, Marincin temporarily in at 3LD or Bogosian higher than 3RD. I suppose you could give Liljegren Brodie and keep Lehtonen and Bogosian at 3rd pair. Either way, this is why we don't trade Dermott. I am okay with this defence short term. Certainly wouldn't be happy if we would have traded Dermott for a 3rd liner.

IMO TOR should play Mo with Holl, Dermott with Brodie and Lehtonen and Bogo

I wouldn't be upset with this, there is a defensively sound player in each pairing. Although, with how often Mo likes to pinch (and fail, apparently) I don't know how confident I am with Holl's legs to be able to compensate.