Does this mean the following is now possible?
Using a single Cerbo GX to monitor (and control via Node-RED) both the propulsion motor and battery as well as the house battery and AC loads in/out. With the propulsion battery selected as the primary battery in use for the boat page display (SoC% and time-to-go) and the motor smartshunt and/or Sevcon CANopen integration for motor data live feed (and USB GPS mouse for speed).
I believe this should be possible even though the MultiPlus II is dedicated to charge the house bank only and to provide AC power onboard.
I have forked the rest of this question to its own topic: Electric boat, propulsion and house battery, Cerbo GX monitoring and MP II AC power supply