Good question on Fackrell. Not many guys dramatically reconfigure their bodies at age 26. Super common to be filling out significantly at 21-22, less so at 25-26. Maybe he'll be able to do so somewhat. All of the colleges are huge into that too, but not to the level of the NFL. And lets face it, there are also probably a lot more PED's and stuff in NFL circulation, so he's got that opportunity too.
Hopefully he improves and emerges dramatically and becomes a much-improved guy. Even assuming he doesn't get all that much stronger, he might still get better at doing what he does, skills-wise, rushing the passer.
For Barney, even if you sign him, I don't think you'd be wised to expect him to be a 3-down guy. If he doesn't set the edge the greatest versus the run, most downs you're not expecting run anyway; he'd not be getting wasted ever running play anyway; and if they want to run on 2nd-and-8 or 3rd-and-6, that's probably a good thing.
Plus, even if the other edge guy isn't setting a great edge, shouldn't be a lot easier if Perry is strongly setting one edge and the LBers and safeties know it's really only the other edge that they need to be watching, in terms of outside runs?
Aren't going to be many every-down-guys in our defensive front. Barwin wouldn't need to be, and Fackrell doesn't need to be either.