I believe only one of those was an employee of the WWE at the time of death (Eddy Guerrero, and it is EDDY not EDDIE just so everyone knows). Hennig, Rude, Hawk, Spicolli, Crash Holly, Duncam Jr. and everyone else weren't with the WWE at the time of their death. In fact, the only real damning one to me, is Brian Pillman and that happened a decade ago.
Evne Eddy had been clean for awhile when he passed. The WWE had actually fired him a few years prior due to him being out of control. They only brought him back when he was able to prove he had recovered.
I am really surprised Sean Waltman and Scott Hall are still alive quite frankly. I would have guessed the both of them to be gone by 2005.