Do not underestimate audio circuit tuning based on listening tests. Good ears and patience can substitute a lot of lab equipment dollars, especially for a hobbyist.
I assume you mean AD85050 (rather than AD8255). And yes, the last paragraph before "Going all-in" is about the idea of driving the I2S. But the I2C config sent to the ESMT chip would have had to be reverse-engineered as well...