Think I'll need to add the giant rune up top to the doc. It appears to be purely decorative. I THINK its supposed to light up when when you use the final rune to open the portal. Just like the runes above the barrier leading to part 2. (which you can get to those and toggle them. Won't impact the raid function)
Skulls lighting up should be detailed in the doc... If I moved it anywhere, let me know. It would make sense if they were, but they're too unwieldy to use. If they end up being the solution... I'll be suggesting a mechanic change.
Kopru symbol number... could make sense. When I get a chance, I'll try shifting the numbers and see if it produces a different result on some of my decoding attempts.