If the customer wants multi-channel stereo, rather than surround, don't bond the rear speakers to PLAYBAR, Group the rear speakers to PLAYBAR (as separate rooms). You'll need to tinker with PLAYBAR's audio delay in order to bring the two "rooms" into sync. In this setup, wiring the rear CONNECT:AMP is optional.

I recommend wiring as many players as is practical. If you have only a few rooms and WiFi coverage is excellent, you can use Sonos in WiFi mode, but SonosNet is more robust. If one or more Sonos units is wired, the system will switch to SonosNet. If it is not convenient to wire a player, wire a BOOST. In difficult wireless situations multiple BOOST's can be used to support dead areas.