The Pirates have the assets to trade for Quintana twice over...it's just a question of how wise it would be to move.
As a Pirates fan I'd consider Keller untouchable (I think BA may have been a little overzealous rating him ahead of Glasnow already...but I wouldn't be surprised if Keller is in the discussion for best pitching prospect by the midpoint of the season, Meadows effectively untouchable given the uncertainty of McCutchen's future and the fact that Meadows essentially represents the Pirates entire OF depth outside of the Majors, and Bell is awfully tough to move given how weak the Pirates are organizationally at 1B (trading him means Freese is the everyday starting 1B with the best internal replacement being drafted 6 months ago).
Still, take those 3 off the table (and I don't think Bell is off the table...he'd just require a replacement elsewhere, which makes it harder to deal him) and there's still the pieces to get it done with Glasnow being a top 10 prospect, Newman making his debut on BA's top 100 at the mid-season at #51 and likely moving up a good deal once the pre-season list comes out (I'm stupidly high on this kid), Hayes being a top 75 prospect, guys like Brault and Hanson being Major League-ready, and guys like Tucker, Craig, Yeudy Garcia, Kramer, Moroff, etc. being in that 7-20 range organizationally.
Like Huntington I may be a bit too smitten with a lot of these guys to pull the trigger. This is where I'd be an awful GM...too enamored with my own toys.