Personally, if Dombrowski signs 2 pitchers, I would start Rodriguez and Owens in AAA and keep the others for depth. I know that that is not a popular opinion, but the more options and flexibility you have, the better. Start the season with newly acquired #1, newly acquired #2/3, Buchholz, Porcello, and Miley. Kelly goes to the BP, which gives the team one less BP position to fill. How nice would it be to have someone as good as Rodriguez as depth to fill in when one of the starters gets injured or underperforms? If Dombrowski only adds one starter this offseason, Rodriguez starts the season with the big club.
Koji and Tazawa should be fine next season after resting this offseason. Add Kelly as a possible late inning reliever.
I have a feeling that one of Kelly or Miley will be traded as part of a package this offseason.
Regardless of how the pitching shakes out, the fact remains that Ben has left the team in great shape. Fix the pitching with a couple of key moves, and we're good to go.