Great thread and overview, thanks for that!
For me it works to control volume with my SiriRemote (1st generation, from AppleTV 4 (HD) ) and my Beovision7-40 MK5 also switches on after a couple of seconds.
However, one question on that switching on: how to make sure my Beovision does not switch on in the 'TV' function, but in the 'DTV' function, to which my AppleTV is connected via HDMI? Are these defaults to be set based on preference? Now I still need to use Apple and B&O remotes to get started.
Thanks!