Thanks guys! HopefulFred, that wall is made of a single row of normal sized bricks. I had enough thickness in the drywall/stud construction that was there previously to go ahead with regular bricks.
As far as the hardwood goes for the theater, I'm probably going to put a small area rug underneath seating in front of the riser. I hope that having people in front of the riser will kill the floor bounce for the back seats. As for the front seats, I'll likely use a reflector that sits on the floor to bounce sound back to the screen wall which will be heavily damped. At the very least, this will delay those reflections, hopefully 10ms or more. I'm going to try a similar technique for the ceiling.
Here is some inspiration for you - this room has a hardwood floor, with a rug
Here is what I understand carpet does (not a lot, but I guess it goes real high +4k)
Hz 125 Hz 250 Hz 500 Hz 1 kHz 2 kHz 4 kHz
carpet 0.01 0.02 0.06 0.15 0.25 0.45
That's a really good looking plot, Elill- I hope I can get half as good as that!
Just sticking my head in the door- still alive, still chipping away. I'll post a few more pics soon. Theater ready for paint but needs front/back/side soffits built and speakers finished. Happy New Year everyone, and here's to getting it done in 2014!