Not trying to be rude or confrontational here, but this topic is definitely something I was interested in, so decided to do a little more testing on Asuma WB and EM Pose buffs stacking in particular.

Team was Iruka, Asuma WB, EM.

Did 4 runs with both buffs: Iruka's mystery hit high 11k to low 12k.
Did 4 runs with without EM Pose: Iruka's mystery hit mid 9k to high 9k.

To me this looks like those two buffs stack. Generally I'd do some more testing but the damage difference was fairly large. Either way just thought I'd chime in, this whole topic of buff stacking is great information to know, and something I really wish was more common knowledge.