You can wire the Arc, but do not wire the 2 x Play:1’s if you plan to use them as surrounds. Another alternative is to not wire anything and maybe run all on your router’s WiFi signal instead - see the below links for further details:

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

But more simply, yes. You can retire the BRIDGE, and use the Arc as the BRIDGE, and upgrade everything to S2. 

• Airgetlam, thanks for the answer, that is what I was hoping to do. I have deleated the S1 app and have the Arc on the S2 app. The problem I have now is getting the S2 app to pick up the Play 1’s without the bridge.  Could you explain how I go about adding the Play 1’s (gen 1’s) using the Arc as the ‘Bridge’?  Oh, just to clarify the Arc is hard wired to the router via an ethernet cable.

I think you have gone about this the wrong way, but I think it can be rescued.  (The following assumes that the P1s are still on S1, which sounds like it is the case)

1 Power off the Arc and uninstall S2 app.​​​​​

2 Leave the Bridge powered off

3 Power on the P1s, and wire one temporarily to your router

4 Download the S1 app and select ‘connect to existing system’  (If you don’t get this option please post back)

5 In the S1 app system settings look for a “compatibility checker” and run this tool.  It should give you an option to upgrade to S2.  Select that option and follow the steps.

Please post back for further guidance at that point, or at an earlier point of failure.

(The direction of travel here is to get your existing speakers onto S2 before adding the Arc, and then set up the surrounds.  But please don’t try this without guidance.)

Well I’ve sorted it, in a round about way. I had already deleated the S1 app before I read the last reply. So I factory reset the Play 1’s and then installed them onto the S2, which required me to connect them direclty to the router as they weren’t showing on the app initially. Anyway all good now and they sound great along with the Arc. Sub next me thinks!