I refuted the one idea because of 3 neg feedbacks out of 7 ands a video loss on one of the pos feedbacks. Thats 4 out of 7 that spoke of losing video signal or more than 50%, which is good enough for me most of the time.
This new plan, included in this post, would work. But I have decided to send all signals to Denon 3808 and then back to the tv's one component input. I have sent the audio from cble box to the audio inputs on tv matching the component video input from rec. This way my wife can watch tv with the rec on, set to cable input, turn down the volume on the rec, and use sound from the tv. Her main concern was turning off all the speakers, especially the sw during regular tv watching while the kid is asleep. As for MIL, I will just leave rec on also so she can watch the same way just needing to use cble box remote.
My wife has had no problem so far she even figured out how to turn rec to cable input after I left it on dvd sat night.
So thanks to everyone.
I wish my tv didn't have such a good picture, so I could upgrade it to an hdmi compatible tv. Maybe in a couple years.