I'd take Kordell, as a back-up, but I'm not sure he leaves Pittsburgh.
Yeah his stats are better, but Pittsburgh has a far better running game, better receiving targets, and he's playing in a system he knows, or atleast should know by now. Mobility in the pocket helps too.
I think Peete's gone regardless. We might be asking Kordell or Plummer. I'd take Plummer. They both have their inconsistant moments, but I think Plummer could have a better upside and he has greater ability for a big play.