I tried compiling the FOCBOX UI sources on my Mac and it seems to have worked just fine. The compiled app is here: FOCBOX_UI_1.1.app. I tested it only very briefly. I can connect to my Unity and changing basic settings worked (tried changing the controls from Forward/Brake to Forward/Reverse and back). Use at your own risk.
Are there plans to releasing the FOCBOX Tool sources? That one is clearly based on the vesc_tool, which is GPL, so you are legally obliged to release the sources.
Nice work on the Unity, BTW. So far I like everything about it a lot… except the missing Mac software.
Edit: The FOCBOX Tool sources are available (same repository as the FOCBOX UI, only different compile options). The compiled Mac OS app is here: FOCBOX_Tool_1.1.app.