Ah… I think I’ve resolved my confusion… the V5_control_rack schematic Multiplexer replaces the zynaptik multiplexer. So I can run buttons and encoders off 0x20 and 0x21, while the zynface adds a third multiplexer for handling the cv_gate I/O, and an extra 8 GPIOs. So I wouldn’t need the additional multiplexer from the zynaptik schematic.
Is this correct?
And then I’d choose the wiring layout of “MCP23017 Zynaptik-3 Zynface” e.g.
Essentially I want to build this User Interface … but with a consolidated main board and break out boards just for the control hardware.

