Ran a EE Cabal last night.. it was fun.
Perhaps one more chest should be included given the number of red bosses though. A chest spawn in the middle of the upper level between the two conspirators might be appropriate after they are defeated.
We did get the first optional chest, but did not do the traps to get the second chest at the end.
I think killing 4 reds before the end fight should merit at least one more chest.