Now for WHAT I DON'T KNOW. I'm not 100% positive that audio content provided via HDMI (or TOSlink/SPDIF) into a 775 will come out the L+R stereo pre-outs due to digital content protection. Anyone?
I'm not sure I am seeing your wiring correctly, but you might consider the RX-V775 as I have. Same as the 675, but has pre-outs for channels.
Why? As Sam mentioned, the inputs that can be played on Zone 2 of the 675/775 are limited to mostly the analog (music) inputs, tuner, net radios. With...