I think only 2 are certain as of right now ... Ober and Ryan ... but ... depends on the rest of the year and ST. Even though Gant has done ... respectably okay ... I don't see him starting next year. I would have added Winder, maybe, to your list ... I think he has the same chance as some you have on there (i.e. Balazovic and Strotman ... neither of whom I see beginning the season in the Twins rotation, along with Winder).
Bottom line ... I can be a cynic and say 4. But, honestly, I just don't know.