The best candidate would be Castellanos. But right now he can neither hit nor field.
Bohm is also a good candidate. He's not half the hitter Hoskins is.
Schwarber is a better hitter than Hoskins, but not by that that much. And could be an even worse 1B.
Hall could probably play there with Bohm or Castellanos taking the weak side of the platoon but I'm afraid that after 50 or 60 starts he'd be exposed as a bench player.
If you go outside the organization you're either not getting a better player or you're not saving enough money for it to be worth doing. You can look at it as, Turner or Bogaerts will replace some of Hoskins' offense, but in that sense you still need someone to replace Segura's.
I'd be fine with Schwarber or Bohm/Hall if they upgrade LF or or 3B (with Castellanos and Sosa both playing at those spots too), it would not improve 1B but could improve the team. Just doing it to help pay for one pitcher or the SS is not enough though.