I've never seen this before and typically Ethernet is used for Ethernet - which is data communication, not for audio.
Audio typically uses a powered amplifier and then speaker connectivity to single or multiple speakers depending on the wiring.
I would get up on a ladder and pull some speakers down and see what type of wiring goes into the back and I would actually figure out what cable is going to what location.
Perhaps this is all done with some sort of locally powered speakers of some sort, which I HAVE heard of, but is very much a specialty product, and should be determined before you do anything.
Since this is not a typical setup, it's important to know what the actual setup is, not just some pictures of the patch panel at the head end. Where EXACTLY does each wire go to?