After some more research, I finally found a complete datasheet for the ES9018 digital-to-analog converter. With it, I should have enough to replace the CS4384 of the XMOS reference design. And by studying some of the kits offered by DIYINHK, I should be able to put together a basic design that is likely to work better than a barebone circuit built around the Cirrus Logic converter. But that covers only one half of the audio interface. For the analog-to-digital converters, I am still looking for some technical documentation related to the ES9102C. In the meantime, I am convinced that using the XMOS microcontroller to drive the audio interface is the right way to go, and I’ll get started with that part soon.