I think that unless Hughes bombs he is a lock and there will be 2 open spots on the bench. Two of Towles, Butera, Rivera, Mastroianni, Burroughs, Bates, Nishioka, Florimon, Dozier, Tosoni will get those spots, but it is too early to tell...
As far as the 3 bullpen spots go (and I agree with your locks) one will probably be Doyle's to lose. I see Burton, Maloney, Wise, Oliveros, Perdomo, Burnett, Waldrop, Vasquez, Gray, Gutierrez and probably a couple more fighting for those. I think the only ones that can be counted out are Bulger, Guerra and Hendriks (for different reasons). Unless either Blackburn or Marquis pitch their way to the pen, which will open a competition between Doyle, Hendricks and Swarzak for the last rotation spot.