If you're not extending Toews and he's willing to extend with Columbus, then I think the Jackets back up the truck for him. Mateychuk, Sillinger, pretty much any future not including KJ, Jiricek, and the 3rdOA is on the table. Jackets also have a surfeit of good depth wingers that Colorado could use.
I don't think Girard is what the Jackets need.
Has Harris played up lineup much? Vs harder competition?
There really weren't defined "1st pair, 2nd pair, 3rd pair" pairings all year. The answer would be "sometimes". But he did get a lot fewer Ozone starts than most of the other D and again, was high up on D in things like Corsi %, Fenwick %, XGF%, HDCF% etc.
He's very much undervalued in Habs land because Xhekaj is fun to watch, and gives big hits, has a bigger shot and fights. But most of the time when the puck is in play, the team does better with Harris on the ice compared to Jack Eye. He's not a star, will never be, but he's a good solid defenseman. I'd rather have him on the ice than Bean, Boqvist, Gudbranson, Blankenburg (who I like when not injured) and pretty much any CBJ D other than Werenski.
Doesn't mean they should trade for him, but to dismiss him as small and weak is silly.