Duchene to STL makes sense. Shattenkirk to COL does not. The only way I see this working is:
A) A third team is involved that wants Shattenkirk. or
B) COL already has a deal in place to trade Barrie and has the framework of an extension in place for Shattenkirk.
I've been trying for a week to figure out who NJ could send to COL as part of a three-way deal where the Devils get Shattenkirk and the Blues get Duchene, but nothing really lines up. For STL, it makes sense to target Duchene as I believe he is the only Top 6 C that has any likelihood of moving before the TDL, I just don't see a deal happening in the division.