I sort of have the same set up with a panasonic 65st30 and an epson 8350 projector. I have all my inputs blu-ray player, dish network, and pivos, feeding into the inputs on my Onkyo 808 and the single output going into Sewell 1X2 HDMI splitter v 1.3 3d I purchased on Amazon. Those split off to hdmi 1 input on my tv and hdmi 1 input on my projector. The Sewell splits the signal at all times so you don't need to worry about changing the output on the splitter just on your LG Stereo. Since all of your audio/video get routed through the LG when you swap video the audio will also be played to the corresponding one. As far as the rear speakers not working during the Direct channels I suspect it might be a setting within the reciever or the direct box itself.