I don't think they would move on from Castro - even if / when Buxton and Lewis get back, we're not talking about the most durable players. You need an insurance policy and Castro's as good as you're going to find.
Thielbar, my personal opinion is they 'should' move on and let Funderburk get the spot. But, I can't see it happening. He has Rocco's trust, right or wrong, and he's a big part of the clubhouse.
Farmer, see Castro and Thielbar. He's an insurance policy and even when struggling to produce, is probably the team's best leader next to Correa.
Santana - possibly. Especially with Miranda's emergence. You could have Miranda and AK at first base and Santana has little to no value at that point. But if the front office kept trotting Gallo out last year for as long as they did, I don't think they're going to dump Santana anytime soon.
Jackson - yes, please. And bring Alacala back.
Margot - yes, please. Hasn't worked out and isn't necessarily needed even with Buxton headed to the IL.