I was leaning in that direction after reading this post from B3OHACK3R: https://beoworld.dev.idslogic.net/forums/topic/universal-link-adapter/page/4/#post-25565 But perhaps I misunderstood.
Not entirly sure, but in option 2 a TV should be able to get the local volume control signals from an audio systems volume buttons sent via datalink. Not sure if that will also work the other way as there has not been any datalink/masterlink compatible TV’s with local volume control. Hope you can get some more info from the real datalink experts