TV ROOM

Hello,

The double brick wall should be fine (well damped) by itself.
Zero Transmission. 
Based on personal experience with concrete foundation wall.
Air space between walls helps. 
Acoustic Mass Panels (even drywall) could be added to a brick surface.
Typical Double Wall Construction with an air gap offset studs and insulation.  Reduces interior area.
The side walls and ceiling will likely be less well suited to contain sound.
The size of the room and shape effect listening levels.
Perpendicular walls and parallel ceiling are the worse conditions.
A large Widescreen TV will reflect energy.
Damping and Placement will help.
Consider an acoustic / suspended ceiling if possible.
Suspended Diffusion Panels for example. 

Get this book.  It's the best resource for not only keeping sound from getting out of a room, but also for optimizing the sound in it.  Given your constraints it sounds like resilient channels in your ceilings and walls may be your best option.  Any half competent contractor or even a handy layman can follow his simple instructions.  In any event, you'll learn a lot about what and what not to do to create a good sounding room.  I found it very approachable and educational.  Best of luck. 

https://www.amazon.com/Premium-Home-Theater-Design-Construction/dp/B0041SUL2E