Hi @Connor
The channel assignments on the original screenshot were 1 & 2. The 218 was set to downmix as needed although it never occurred to me that this might apply to 5.1 or 7.1 setups. I come from an era when downmix meant stereo down to mono!
I also didn’t understand that the parametric EQ could be standalone. I opened the procedural EQ, saw the parametric stuff and took it from there.
I have now recreated the filters in a standalone instance of the parametric EQ.
There doesn’t appear to be a channel assignment at the bottom though. Am I missing something?
Should I also switch the 218’s downmix as needed to channel mapping only? Unfortunately, as I said earlier, I can’t test any of this yet. 
Thanks for coming up with all this. I’m embarrassed to think it might have been finger trouble all along!