Looks like you're off to an excellent start. Just be careful running a second set of speakers off your AVR. The same amp will be driving both speakers, so if you've got two 4 ohm speakers, that'll be a 2 ohm load for the amp, and the 4 ohm spec is average. You could be down to a single ohm at some frequencies.
Many amplifiers struggle to produce the current needed by that low of a load, and while it may "work", audio quality is likely to be effected. Distortion will likely increase substantially when the amp is taxed in that way.
I also agree with the folks suggesting a trial of a dedicated 2-channel amplifier. You might look around and find a few with a good return policy (music direct, apos, etc) and then demo 3 or 4 contenders at the same time. You'll learn a lot about what the speakers sound like and get a sense of how sensitive they are to different amplifier flavors. Just choose the best and return the rest. Maybe you'll get lucky and find out that your Yamaha or Sonos was the best option anyway.
Many amplifiers struggle to produce the current needed by that low of a load, and while it may "work", audio quality is likely to be effected. Distortion will likely increase substantially when the amp is taxed in that way.
I also agree with the folks suggesting a trial of a dedicated 2-channel amplifier. You might look around and find a few with a good return policy (music direct, apos, etc) and then demo 3 or 4 contenders at the same time. You'll learn a lot about what the speakers sound like and get a sense of how sensitive they are to different amplifier flavors. Just choose the best and return the rest. Maybe you'll get lucky and find out that your Yamaha or Sonos was the best option anyway.