I've upped the ante a little bit and decided to purchase the Control:10 system, which includes the SourceOne (that I will probably resell) and the Ensemble. The Control:10 unit will go in her office (not accessible to the public) so she can do importing and playlist creation there and listen if necessary. I know that Control:Mac software is available, but it is not the greatest though it does work.

The ensemble will then be providing music to all three studios and if she expands we are covered for a few more zones.

Will there be any issues with using a Control:10, TwinStore, and Ensemble together?

System #1: Control:10 and TwinStore.
System #2: Control:15 and Ensemble