I have settled on a final configuration using PurePath Console 3. I used the End System Integration Tab to dump all register configurations to a .H file.
When iterating now through the registers list from a host microcontroller's I2C peripheral, the ADC6120 is not configured in the same way as with PPC3. Are there any additional reads/writes that should be done after sending over the list of register configurations?
My I2C peripheral settings are:
I2C address = 0x4E (or 0x9C 8-bit address)
I2C clock = 400 kbits/sec
I can see all I2C transactions on the bus using a protocol analyzer so I'm confident the bus is stable.