I think Stephenson is going to be looking to cash in, and he's going to want term as well. The last 3 years, he has outperformed his contract. I could see him signing 5 x 5 somewhere.
Colton doesn't score as much and has 3 years left at 4 mil. He might not cost a lot to acquire since Colorado is looking to clear cap space, and he's younger than Stephenson.
Either could be an option depending on what other moves we make. If we are going to upgrade the defense, we have to factor in the long-term cost. Like, if we trade for Chychrun, he will need a new contract next summer. Signing Stephenson or trading for Colton would make that a lot harder, given the other players who will need new contracts.
We may not be able to address every weakness this offseason. If push comes to shove, I'd rather fix the defense, since we have prospects who can fill in on the wing. We don't have centers, but we can bring in someone on the cheap to provide some insurance there, preferably on a 1-year deal. Maybe we trade for Lars Eller, Nic Dowd or Jake Evans, or sign Teddy Blueger.
That said, I'm not sure the right fix exists for the defense, barring a trade for a player otherwise thought to be unavailable. It's easy to suggest trading Trouba and/or Lindgren, but finding the correct replacements is the real trick.