So, the turntable would connect to the receiver in the ‘phono’ input, in the lower left of the picture. It’s designed to be of the appropriate level to not need an external pre-amp, it’s built in to the receiver. 
 

In order to get any signal from that receiver, however, is somewhat complicated, as it has no ‘tape loop, and isn’t really designed for that type of use. You could connect cables to ‘Zone Out Zone 2’, which would then go to either the analog input on a Sonos Five or a Sonos port. Again, this receiver isn’t designed to be connected to another device, so that Zone Out might be amped, or not, and might require a lot of nurturing to get the input level correct to the Sonos. 

The Sonos Ones would then be ‘grouped’ with the analog line in on the Sonos Five or Sonos Port.

If it were me, I’d dump the Yamaha completely, put a pre-amp on the turntable, and then connect that to a Sonos Port. Or Sonos Five, if I needed another speaker. That Yamaha, although a nice piece of electronics, isn’t really designed for this kind of use. 

There is no way to directly connect the YAMAHA output to your ONE’s. You would need to add a SONOS product that offers a Line-In, such as PORT, AMP, or FIVE.

Yes, you could use the YAMAHA as a phono preamp, however, be aware that there is an input selector and a Volume control associated with the ZONE2 output. You would want to set the ZONE2 input and its Volume at a convenient settings and then ignore them because you will routinely be using the SONOS Volume control and input selection. -- However, always keep the ZONE2 Input and Volume controls in mind because at some point someone will discover them, modify them and potentially upset your turntable integration.

In my opinion a simple phono preamp would be an easier solution to manage and save some space. If you have no further use for the YAMAHA, sell it in order to finance purchasing the phono preamp.