The RPI pins that are used by the Codec Zero for are not listed in its documentation and makes it hard to know if it will work with other RPI hats. https://www.raspberrypi.com/documentation/accessories/audio.html#raspberry-pi-codec-zero
This should be added. Competitors have entire pages devoted to these details: https://www.hifiberry.com/docs/hardware/gpio-usage-of-hifiberry-boards/