Yep, HDMI standby passthrough does just that, it passes HDMI signals even when the receiver is in standby.
The 661 can drive two speakers from its EXTRA SPEAKER terminals. These can go in your remote location and can be accessed when you assign them to Zone 2 in setup.
You might consider an X-10 Remote Repeater
that takes IR, converts it to RF, sends that through the wall to an RF receiver that converts the RF back to IR and blasts the equipment with commands.
If your cabling run is short, then a Sewell IR Repeater Kit
might work for you. Sewell also makes extension cables to extend the length. The biggest obstacle with this type of kit is the emitters cover the IR ports of the components and will obstruct their reception of commands by a remote that's in the same room. IOW, this kit is for gear you've stuffed away, yet still need to control. So, on second thought, it probably isn't the right solution for you. But, eh, I've already typed it, so I've left it.
Either way, you'll need to get a learning remote to copy the IR commands from all the remotes used to control the stuff in the room with the receiver, but they're cheap.