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All of the instruments, including voice, should be available in the main library within a single tab, not in a sub-directory, especially settings [the 'geek' tab', you don't want folks messing around in there]. The 'Custom Group' tab [settings> library>Custom Group Name] may be a candidate for this purpose if the necessary work flow can be accomplished using it.

If the custom tab is viable then, for the musician:
Turn tablet on>main library displays>select custom group, the only tab showing [instruments]>select instrument>select set list [should be the only one]. [settings>library settings>tab selection and order][A reason for not using settings for instrument selection.]

The manager would be responsible for prepping the tablets and maintaining the base library. I'm not sure how each tablet would get the correct setlist currently, probably separate libraries. Each tablet may require its own visible id so it is always issued to the same instrument.
Note- Using the base library on all devices would be easier if selecting the correct setlist when the instrument was selected can be made to work. I think that's where versioning is supposed to work.
I don't manage a group so this is just my guess on a starting point. 

I use the custom tab for a different purpose.