Interesting results so far – the fact that the MCL2AV AUX socket connection allowed control was useful, but I too don’t understand why there was no sound. I thought that pins 1 and 4 always output the sound from MCL2AV.
My gear is put away at the moment so I think it will be next week before I am able to try anything similar (with a known working MCL2AV), but until then I will be following with interest!