vgmrips

PPZ8 exists in the PMD driver, and it seems that the current software cannot record it. My idea is to record PPZ8 to other alternative chips, such as RF5C164 or other multi-channel PCM chips.

Short answer: Currently there is no way to record 86PCM. I didn't have time to implement 86PCM logging into the NP21 VGM mod yet.

Also, it is impossible to log PPZ8 to multi-channel chips by capturing 86PCM. PPZ8 itself does all the mixing in software and 86PCM just gets the final mixed wave stream.
In order to log PPZ8 to multi-channel chips, you'd need to modify the PPZ8 driver itself to use those chips instead of mixing all by itself.