TAS5162 example schematic questions
The original schematic is found here, in page 19. From a quick glance of the datasheet and the schematic:


the microcontroller is there to read the outputs of pins 2 (/OTW - overtemperature warning) and 3 (/SD - shutdown) and take action.
the TAS5508 in the red rectangle is the IC that does the actual audio processing and outputs a PWM signal. So, I'd take it's not optional unless you have the audio in PWM from somewhere else.