I think Cishek is a pretty safe drop. You have other decent save options, especially with Bell getting the closer gig back for now. If you'd prefer to hang on to Cishek though, I'd think parting with Hunter could be a pretty harmless option. Hunter's got all the personal stuff going on, he was awful even before that, and the Angels offense is also horrible. I don't think you'd regret losing him, and Choo is an upgrade IMO. OF for OF swap, with the potential for more production.
If you're comfortable dropping Cishek, I'd do that first. If you'd prefer to keep the saves and just do a bat-for-bat swap, I think you're right: Hunter's the best option and would cause the least damage to lose.