I have included in this topic a JPG of the cradle connectors and fortunatly it works as I hoped

As you can see in the Garmin harness specs the items of interest to me is #4,5,6. On a GW in the sound harness going to the for example the driver headset you have five cables: mic+/-, audio L/R/-, which means that #4 is rather straight forward. Now comes the part I need some electronics wizard help with. #5 is audio output which I figures is the way the spoken directions and if I have a phone BT connected to the unit the sound from that comes to the bikesystem. #6 is audio input which I figures is the one that I connect a MP3 player to if I have one.
Have I gotten the base connections right or is there someone with any other opinion?
Since I´m not trying to get music into the system on either this way could it maybe be a better idea to get an input device each for the bikes and do the mic separate from the headset cable?
Or do I do one connection point for both mic and audio on the headset cable?