Yes you can use Sonos as a source. However feedback is a little different. THere are some feedback modules for Sonos, but I've heard its quite the gamble to go with.

We've done two systems so far. One was 4 zones of DA with 2 lighting loads and a family room (no avr). The 2nd was 3 zones of DA, 3 lighting loads and a family media room with AVR. Both systems have one PTX3, One PTL4, one audio keypad and the Mobile Pro App.

I'm just about to start installing my personal system and hope to soon be learning a lot more.