Left channel + input gets ONE wire.
Left channel - input gets ONE wire.
Right channel + input gets ONE wire.
Right channel - input gets ONE wire.
There is no reason to double up on wiring on the inputs to your volume control. It will just make things difficult, especially with volume controls.
Output can be doubled up if you are using single speaker stereo type speakers. But, if just using traditional speakers, then left +/- to the left speaker and right +/- to the right speaker.
I'm not sure how a zone ended up with 3 speakers in it. That goes against most of how I would ever wire a typical room. Especially since speakers are typically sold as pairs. But, if that really makes the most sense, then that's what it is.
Sonance makes perfectly fine speakers. Their build quality tends to be better than most, but their sound quality really isn't anything better than what you can get at half the price. Their 8" directional woofer/tweeter models are a real step up in terms of quality and worth it if better than typical audio is demanded.