If you need more than 8 SP's as depth, you're f***ed. Elias has a better chance at a spot start than Owens or Johnson. It's not that hard to find a AAAA pitcher.
For Smith, some are saying he should be ready by opening day. DD is holding off on announcing anything like that and hinted it might not be that close.
They did great mainly due to Price and Porcello since they both put up a ton of innings. After that, it was three days in a row of hurry up and get the bullpen ready.
http://boston.locals.baseballprospectus.com/2017/01/06/roster-recap-no-one-knows-what-to-do-with-drew-pomeranz/
Not sure if anyone had read this article yet, but it's a good glimpse of how the Pomeranz is playing out.