I dont think it does strip the audio. My Sony TV can toggle between Audio System and TV Speakers. In fact as you replied I tried setting my TV to TV Speakers and I could get both audio from my YouView box (connected via HDMI) to output from the TV speakers and Spotify (inbuilt network on the Yamaha AMP). So I believe from my testing that the HDMI signal always includes the audio stream as well.
Edit: One interesting thought that I just realised. When I swap to the TV speakers, then my AMP stops outputting sound via it's inbuilt speakers. So I wonder if maybe its just HDMI-CEC that is telling the AMP to either output audio via the speakers or via the TV... So maybe my plan won't work then!
Might have to look at a new AMP with a Party mode then!
Edit2: Tried switching of HDMI-CEC on my TV and I lost audio on the TV and audio is always from the AMP now. So you are right, it doesnt output audio to both at the same time. I'll have to buy a AMP with Party Mode then...
Thanks for saving me some money! Was just about to order audio extractors and various cables etc that I won't need!
Edit3: No sorry, ignore that! I just saw if I switch of HDMI-CEC on the AMP, then I can choose if I want audio to be outputted to HDMI, AMP or both. So I can get it to output to both at the same time!
So that puts me back to my original question, would it damage the amp if the audio is looped back and selected in the main zone?
Or can I somehow block so the analog input is only selectable in Zone 2 and not Zone 1?