This is a terminator T....
Canare BNC 75 ohm Terminator $5.55 each or $5.00 each for 24 or more.
You have a lot of digital connections going all over the place and not much reason to do so.
Why are you sending SPDif to the PCM? It would probably be better to use analog cables on a AUX bus.
ADAT connections carry both audio and clock information. Try to remove the BNC cables and clock via ADAT.