According to Ubi, they want you to use optical for audio, not hdmi, due to lag issues. They posted a diagram online on how to setup your xbox one, located here
Currently my Sony Bravia TV, is connected via Hdmi into my HDMI In (ARC) on my Denon 2113CI receiver. I also have my Amazon Fire TV plugged into the receiver via HDMI. The Dish hopper runs HDMI to Xbox One. Then another HDMI goes from XBOX one to my receiver.
What do you suggest then for using optical? Your diagram on your webpage shows plugging the TV into my xbox one. Well if I do that, then when I use my Fire TV, which is plugged into my receiver, that isn't going to work.
Should I just plug in the optical cable from xbox one, to my receiver, while also having it plugged in via HDMI, then just set xbox one to PCI and be done with it?