Not quite sure I understand what you’re saying, so let me rephrase, hopefully in a way that can be understood.
If you’re connecting one Amp via ARC to your TV set, the other Amp can be connected wirelessly (WiFi) to the first Amp, and you’ll have two front speakers plus an interpolated center channel from that ARC connected Amp, and the second (wirelessly connected) Amp would be powering the surround speakers.
Is that what you’re intending?
The only other speakers you could add to that Sonos ‘room’ is a subwoofer, or two subwoofers if they’re Sonos brand.
Oh, in the case I’ve listed, there would be no lag associated in either TV or streaming music playback. However, if instead you set up the second Amp as a separate Sonos ‘room’, the second Amp would not be set up as ‘surround’ speakers, and there would be a delay if the second Amp was grouped with the first, but only when playing through the TV’s ARC. When grouped to play music, the two ‘rooms’ would be in sync.