With the Sonos soundbars, Arc/Beam etc; the TV audio only can be swapped to the Ace headphones - but you can’t swap the music audio, at least I’ve not ever come across that feature - it’s just any audio that the soundbar receives over its HDMI (or Optical) connection.
I don’t have the Amp, but I’m ‘guessing’ the same may apply to that if it’s acting as the primary device in a Home Theatre setup. As far as I can ascertain here, there’s no way to swap the music audio to the Ace headphones from a Sonos Five… the Sonos App doesn’t cater for a music audio swap with any Sonos device.
I get around this music playback limitation by connecting a Bluetooth Transmitter (TX) to the output of a Sonos Port and then connect the Ace to the TX and that potentially gives the Ace access to all the Sonos App music services, including Sonos Radio, but obviously i can only listen to such sources when at Home - no way to take these things out & about.
Does that assist?