Well went ahead and did the swap. For anyone else interested here are a few pictures.
Pictures of it removed. Pretty small opening left behind, measures 30 3/4" w by 2 11/16" h
The Sonos beam I wanted to install measures 2 5/8" high, a sweet 1/16" to spare.

A little wood putty and a support brace to secure it and it was good enough to call done.
I decided the blank side openings didn't bother me enough to worry about it, but if anyone has a clever way to hide those better please let me know.
For reference, the back of the junk Furrion.
