In the context of that post I meant four veteran locks as in we'll have four veterans who are guaranteed rotation spots heading into spring, barring injury of course. For roster management purposes I think that's important to keep in mind for gameplanning how you'd get Wiggins to MLB.
For the names specifically, I'd say it's very unlikely Shota goes anywhere, but admittedly it's not a lock. I'd put Taillon in a similar boat. I think if Tom juices payroll this winter (unlikely, but this would be the time to do it if ever) or if Jed has no intention of holding onto Tucker, then the offseason gameplan would clearly be pitching pitching pitching, and there'd be money to both add a SP outright and also upgrade from one of the mid priced vets.
I'll say I'm not super worried about Shota. He probably doesn't have another year like last year in him, but he's still missing bats and the models still like his stuff. There's probably some positive strikeout regression due that would make his peripherals look a lot more mid-rotationy. I think picking up his option is still a + EV move, even if its not the crazy bargain it looked like a year ago.