I do not think that speakers need to be connected to the BM5. I have a BS5/BM5 connected by Masterlink to a BV 10 and a BV 7. Both tvs have speakers connected to the tv. I can control music with an app on my iPhone and iPad in both rooms, through speakers connected to each tv. I do not have much experience with MediaConnect as I could not get it to work at all for me. I have been using eLyric.
Beovision 7-55 with Beolab 7-4, 9s and 4000s
Beovision 10-40 with Beolab 1s and 6000s
Beosound 1, 5, 2000, and 3000
Beotime, Beotalk, Beocoms