Basicly you can connect any 'analog-out source' this way.
You could use the Essence (just the box and set as fixed line-out).
You would control that either via the Beomusic iOS app or through airplaying or google casting.
This way you should be able get the sound (A.Aux) in every linked room.
Or you could use the output of the Alexa.
Finally you could connect the output of the Alexa to the line-in of the Essence (this has autosense) and have all, that you required for ;-)))
As for your question about your tv in the other thread:
If the tv and the BM/BS5 plus the speakers are located in the same room
(and the speakers are placed ideally on either side of the tv),
my advice would be to have a look at the BeoPlay S8 hub - just like others have adviced.
MM