Yes SPST would be enough.
Unfurtunately I don`t have the schematic of the radio.
Basicly I traced and cutted SDA and SCL wires going from the radios main board with mcu to frontplate with lcd.
Now I need either:
Radio MCU ---->display
or
Arduino--------->display
For ibus is just matter of disconnecting wire that comes into the back of the radio.
It would be hard to write schematic as it is 3layer pcb, I can search and measure some things if anything particilar is needed.