Is there a question?

I just updated my question.

I have an Arc and sub. Iwant to add speakers in the rear for a home theater effect. 

Era 300s will give you the best Atmos effects.  Less expensive options are Era 100s or Ones, which are still effective as surrounds.  I consider Fives to be overkill.

Thanks

Look at the positioning requirements for the 300 and if you can follow them then the 300 are a great choice. If not maybe the 100 would work better in your space.

Ones and One SLs are showing up in last chance offers so I’d lean to a 100 despite the slightly higher price at this point.

I have the Arc and deciding on rears. There’s about 1ft of space to the wall at either side of our sofa which is placed against the back wall of a 15ft long room.

So the room is 15ft by 9.5 ft and 8ft high. The TV + Arc are 14ft in front of the sofa with little room on either side of the sofa. If my wife and I watch something together we would be very close to surround speakers (unless I put them near the ceiling). Is the room too narrow to consider rears at all? 

I've had my Play 1's pretty much right next to my head for several years and didn't find it a challenge, not quite optimal but sounds fantastic together with my Playbar and sub.
In addition, you can set them via Trueplay and you can also turn up or down the surround sound (your rear speakers).

In other words you can adjust your speakers to fit any room.. You won't regret it :)

Mm. Just been to shop (H Norman) and sales rep said it wouldn’t be ideal and the Arc is such a beast it wouldn’t make a lot of sense in a room that size. He said even the mini sub would be a bit of a waste. I have an added issue of only having one socket in the room and I believe the Eras need to be plugged in 24/7. 

With that space maybe the IKEA picture-frame speakers for the rears?

They would be happy on an extension cord so the single outlet shouldn’t be a problem.

Thanks for that. They definitely look like an option. BTW, do you know if I unplugged surrounds every night, would they need to be re-calibrated with trueplay when plugged back in?

Nope, we unplug our surrounds, and the Arc and Sub too with no need to do anything other than waiting for them to boot up when we are ready to use them.

Sonos, and I, don’t recommend powering speakers down on a regular basis as it really the way Sonos has designed the system. I power down things that go unused for weeks or months at a time but only because we have really ugly power prices.

I’d just run an extension cord to them.

Having a think about a pair of Symphonisk table lamps. Lamp + speaker in one would solve the problem if the sound is good. Reviews seem to be mixed.