Dan,
If the G-minor has an expression pedal input that can be transmitted over CC, then yes, you can assign it to a MIDI CC and control it from there. Otherwise, the MF is either a MIDI thru box or a transmitter. As either, it can receive MIDI commands and respond, but the MIDI transmit functionality either generates new and isolated MIDI commands or passes commands from input, but not both.
To me though, the G-minor sounds like a redundant piece of gear. The MF will do everything it does (send program change and MIDI CC) plus expression pedal control. Is there something in particular you need the G-minor for that you don't think a factor pedal will do?
