Not really….although maybe?

First, Sonos doesn’t make a center speaker. The Arc Ultra comprises front right, center, and front left, so there is no way to split that into separate right and left channels for your Edifier speakers to use. 

You could do what I do, and have separate front speakers from your Home Theater speakers. If you were to use a Sonos Amp, you could drive a pair of separate speakers that flank your Arc Ultra.  You’d set up a second Amp to drive the surround speakers, that Amp would be ‘bonded’, in Sonos terms, to the Arc Ultra and drive that second pair as surrounds. If you were then to ‘group’ the two Sonos rooms when playing music, they’d all play in sync. 

I tend to use Alexa to ‘resume’ or ‘pause’ an already existing playlist, I don’t have much experience beyond that. If I’m trying anything more complex than that, I use my Sonos controller app. 

Many thanks, I feared as much.

Looks like I’ll have to add more Sonos products to get sound behind me.

Regards and thanks again.