Based on above info the audio interface through mic/speaker should look like this:
RJ-45 pin 3 (Ground) → 3.5mm TRRS sleeve (GND)
RJ-45 pin 4 (PTT) → 3.5mm TRRS ring 2 (RIG_PTT)
RJ-45 pin 5 (ME) → 3.5mm TRRS sleeve (GND)
RJ-45 pin 6 (MIC) → 3.5mm TRRS sleeve (RIG_AFIN)
3.5mm TRS tip (EXT SP) → 3.5mm TRRS tip (RIG_AFIN)