About the steering wheel:
I have virtual cockpit from Octavia III FL and the buttons on the steering wheel are working (except for the button for travel assist (right top corner button) and I can't change VIEW, everything else is working, the button for heated steering wheel too.
Regarding to coding, I need only to enable the option, that I have the button on steering wheel.
About the settings on your Columbus regarding VC, you need to have Gateway 3Q0 and it should be working with correct coding (the settings in infotainment)
I don't know about any other workaround. Right know with my friend, we would like to try to create a "translation" unit for LIN communication - example: If you press right left button, it will send to car "VIEW" button click, so far it looks like not possible option, but we will try
Heated rear seats - just wirings and add heating pads
Additional independent heating - I mean auxiliary heating and about tri-zone climatronic, I am not sure, what is needed to be change :/
rSAP retrofit is consist of two LTE antenas under the rear bumber and coaxial cables to infotainment unit, nothing else
Media Command is SWaP code, but it is not so useful I have used it once, I think. And I think, that it is available for MIB2.5