Question Can the tap tempo on the G-Major / G-Major 2 be controlled via an external MIDI clock

Yes, the G-Major can sync to incoming MIDI clock. In the MIDI/UTIL menu you just have to set the MIDI clock seting to "ON" and of course you need to set the right MIDI receiving channel to receive the MIDI information. The Midi channel is also set in the MIDI/UTIL menu.