Not sure how to get behind your TV configuration cause ours sits on a steel bracket mounted on top of the fireplace cabinet. I've already moved the TV back so I would have room to put a sound bar by just relocating the bracket. Ours also has a cupboard under the TV and above the fireplace and that is where we put the DirecTV receiver and a BluRay player.
2011 Georgetown 378TS in FireMist
2013 Jeep Wrangler Toad
Kirby the Old Dog, passed but still in our hearts
Max E. Dog, the new pup
Eureka the Old Cat, still hangin' on