Here some inputs :
While Spirit kings are under a shield effect, they cannot be hit by any "new" spell. It includes a new DoT application (but not a tick of an existing dot) and any new direct spell. I think that auto attack works but a windfury proc may be proccing the shield.
And yeah, whenever someone procs the shield, there is an emote with his nickname (blizzard fail check :p).
The fact is that whenever a person fails, every time the same "reason" keeps coming back : "i did nothing"
So it would be very very nice to see what spell did proc the shield without having to go check the logs. I'd like to see that info in chat as soon as possible to yell at the failman.
Damage to the raid are (imo) not needed as it should cause a wipe.
Yeah, no need here to print into chat, just save it for after combat analysis.
Yeah it's a bit complicated. When the boss gains his Cowardice buff, any damage done on him gets reflected partially (depending on his current energy). So when he's high on energy, he should reflect a large amount of the damage he's getting.
Then, DPS player should pace their damage to stay alive, and I let you wonder how many are dying to that ...
To count this, yes, you should add the Cowardice damage (DoT refreshed every time you hit the boss like the Ignite mechanic) between aura gain and aura removed of the boss cowardice buff.
For the volley thing, you are correct, there are 3 different spell Ids.
For the chatlog, can't you catch the CHAT_MSG_MONSTER_EMOTER event ? They appears like this in my logs.
CHAT_MSG_MONSTER_EMOTE#Ninjouz caused Retaliation.
CHAT_MSG_MONSTER_EMOTE#Ninjouz caused the Darkness