Yes, when you wire one device, that creates SonosNet.

SonosNet is a dedicated mesh WiFi network only for your Sonos speakers, which connects through the wired device.

However, any portable products (Roam and Move) will always connect through your router’s WiFi.

See https://support.sonos.com/en-us/article/choose-between-a-wireless-and-wired-sonos-setup

I have a combination of wired and wireless primary speakers.

Following advice here I have all Surrounds and Subs connected wireless.

I like to wire all the easy to connect ones to give me a more stable system and less wireless data traffic.

I have a similar question. In my living room I have 2 x (Play One SL); a Sub; and Playbar.

I have four other sonos one SL’s in my house outside the living room. 

My wifi and mesh are all the same network. I also use google home for everything and right now it’s all on the same network. 

1. Will I be able to connect my living room speakers via ethernet and still be able to control them WITHOUT putting them into SonosNet mode? I think as soon as I put them into sonosnet mode, I no longer can control them with google home. But I haven’t tested this yet. 
2. The goal is to free up bandwidth on my wifi by connecting my four living room speakers (2xOne-SL, sub, playbar); but still have my four house speakers; and still control them all on the same network, albeit ethernet and wifi. 

Any ideas? 

Why ask the same question twice?