I think any advice here depends on quite a number of things…

• Where the existing in-wall speakers are located in each room.
• What you’re looking for in each room, TV/Music/both?
• Location of TV in each room in relation to the speakers/furniture etc.
• The location of the existing older (Connect) Amps, keeping in view that the new ‘Amps’ may perhaps (ideally) need to communicate direct to any main Sonos HT player (Arc/Beam etc.) over a 5Ghz ad-hoc WiFi connection and so could be out of reach and ‘might’ require additional cabling to the room(s), or the Amps may need to be moved.

So I think much more information is needed about the layout of the rooms and devices. You might be best to get an installer out to look at your current situation and your requirements …and then take things forward from there.

Thanks Ken

Some rooms music only others mix of music/tv

Music only rooms the speakers are in ceiling 

we use Orbi mesh network for home Wi-Fi 

Room breakdown:

Main tv room has existing sub and rear wall speakers. Thinking of adding sound bar here in addition to wall speakers. ?assume need amp here

Patio has existing wired speakers and would need amp

3 other rooms with ceiling speakers for music only - ?combine on 1 amp

3 other smaller rooms with tv needing only sound bar and no wired speakers - ?so no amp needed

Yes use the Amp for the in-wall rear surrounds, but put the Amp in the room so it can communicate with the chosen Sonos Soundbar. If this is the main room I would go with the Sonos Arc.

Note: My advice is don’t put the Amp in another room/cupboard where it cannot communicate ‘direct’ with the Soundbar. Put the Amp in the same physical room. 

I assume it’s a Sonos Sub as that is the only Sub that will work with this type of setup, you can’t use a 3rd party Sub.

Yes just replace the current older Amp with the new Amp.

I assume there are two speakers in each room - you are best to use 2 or 3 amps here, assuming they are not Sonance speakers, or you could insert an impedance matching switch and switch between the rooms with one Amp, but I sometimes think it’s best to just go with three Amps, one for each room.

As they are smaller rooms I would go with the ‘Beam’ and you can always add Sonos One SL’s if surround audio is needed further down the line

@Jbitter,
As you are using Netgear Orbi mesh WiFi - you may also find this thread helpful:

Sonos on WiFi Mesh

Thanks Ken this is very helpful. 
 

Follow up question. For a room using tv + Sonos arc + wired rear wall speakers (non Sonos) with Sonos amp. Is the tv sound controlled with tv remote for all speakers including the wired speakers? 

Yes, the Amp (and connected Speakers) (and Sub) are ‘bonded’ to the Sonos Arc as surrounds and in the Sonos App they become one single Sonos ‘Room’ controlled as a single entity.. so the ‘TV remote’ will control the volume to all as though they are one speaker.

There are options (slider bars) in the Sonos App to shift the audio about between the Arc and the rear speakers or vice versa. or to switch off/on the Surrounds altogether and just have the Arc only playing.

With music playback there are also options to play ‘Full’ stereo audio to all speakers, or you can set the rears to play ‘Ambient’ supporting audio for the Arc instead.

There are two ways to link a remote to the Arc… 

1. Using infrared - Any IR TV remote can be setup in the Sonos App to control the volume of the entire Sonos HT with the TV powered either ‘on’ or ‘off’.
2. Using HDMI-CEC - If the Sonos Arc/Beam is cabled to the TV’s HDMI-ARC/eARC port, the TV remote that controls the TV (Infrared/RF etc.) can also control the HT volume and you will probably also be able to power the TV on/off in most instances, the volume control however is just whilst the TV is powered on.