Hi,
I would like to help you out, but I'm not sure where to start.
Maybe some other members would be more qualify than I to fix you up.
* Personally, I woud start all over, and go simple; like a Pre/Pro (Multichannel
Surround Sound Processor), a multichannel power amplifier (forget about biamping), and you can even use this system for 2-channel Stereo listening.
-> You probably can use your actual power amps.
** I think SIMPLICITY is the key here, no?
P.S. For a good Pre/Pro, I recommend the Onkyo Pro PR-SC886P.
It will do you good in your particular system, I believe.
P.P.S. I'm sure other people will chime in.