INMP441 and total SNR

Hello!

We're building a real-time microphone beamformer using 32 of your INMP441 microphones. One question that popped into mind is the overall SNR of the system. If we sum say 32 coherent signals together we should get an increase in signal strength of 30db and at the same time the microphone's noise is summed together incoherently and it will add an 15db of noise. So the the overall SNR would have risen 15dB compared to a single microphone.
Now my question is, are the noise completely incoherent from microphone to microphone? Could there be some coherency if all the microphones are run with the exact same clock in the same phase? Like some component of the clock signal would get translated into EIN?

Thanks,
Jonas Nyberg