In order to have any “surround” speakers, you need one of four Sonos devices to be the “front” of the system. You need the Sonos Amp, driving a pair of your own speakers (non-Sonos), or a Sonos Beam, or a Sonos Ray, or of course the Sonos Arc.
These are the only devices that can separate a “front” signal from a “back” signal, it can not be done via AirPlay 2.
So, in direct answer to your question, yes, the Beam (gen 1) can be used as the front three channels of your home theater, and the two Symfonisk speakers, assuming they’re the same type, can be then used as surrounds.
The PLAY:5 can be “grouped” with the home theater system, but it can not be “bonded” as part of it, all the the TV input will be delayed by at least ~75 ms, but when streaming music, both the PLAY:5 and the home theater room will be in sync.
thanks for the reply man, one last question, if I get the beam gen1, can I just use it with airplay? I have a projector so no HDMI ARC for me, can I use it like I use the 2 Symfonisk?
thanks for the reply man, one last question, if I get the beam gen1, can I just use it with airplay? I have a projector so no HDMI ARC for me, can I use it like I use the 2 Symfonisk?
You will only get stereo from Airplay, no surround sound.
I have the impression that AirPlay 2 to any non-Apple device is always stereo. I think that you can use AirPlay 2 to “send” a higher quality signal to an Apple TV, but it’s my opinion that at that point, it’s only telling the Apple TV to actually go out and get the stream, and you’re not really streaming via AirPlay 2.
Could be wrong on that last part, but I agree with @jgatie that AirPlay 2 from an Apple device to a Sonos device is *always* stereo. Even if the Sonos device being sent to is able to interpret better signals, it’s alway through either optical or HDMI-ARC/eARC, and never via AirPlay 2.