Mark, in regard to your freakin' questions about your freakin' subs in your freakin' room, my guess on 1. is that yes, the BFD would allow an overall increase in bass after the peaks are lowered.
On placement of two subs to help with room modes, note that the paper by Dr. Toole and his colleagues at Harman(which you should certainly study if you haven't done so)basically suggests that placement in the middle of opposite walls(either front and back or on each side)is helpful(if practical), rather than the positioning which you have. Opposite corners also showed some benefit.
