Yes, which layout works the best for you?. From the last test it seems that all microphone pins are sharing the same ADC. Have you ever tested how it behaves at Windows?, for example: can you use the internal an external mic at the same time, or the headset mic + external mic?.
Layout 0. On Windows when I connect the apple headset or my bose QC25 headset, the microphone of the headset is used (I can't choose the internal one when a headset is connected and on windows I've seen that the internal microphone has the mention "array" in the name)