When I personally think of a toggle variable I think of on and off. 0 being off and 1 being on. When you define the current variable it's default is 0 so I would probably then set the variable to 1 when you want to toggle the variable on (active).
Also, since you want to change a variable when a character is killed I would put it into the destroy fpi. The following is what I would do for the fadecorpse.fpi.
=========================================
;Artificial Intelligence Script
;Header
desc = Fade Out Disappear
;Triggers
:state=0:state=1,
globalvar=14
:state=1:
setvar=1
:state=1,alphafadeequal=100:decalphafade=0
:state=1,alphafadeequal=0:state=2,destroy
;End of Script
=============================================
Now, I'm at a loss as to what exactly you want done with the second character. However, in the script that you want to make the change:
:state=0:globalvar=14:state=1
:state=1,varequal=1:runfpidefault=1
Now what might be working is the logic for running the same or a different main script for the second character. I guess where I'm at a loss is why would you want to run the same script that was already assigned to the character originally?
Plystire's logic is correct so I would say it has to do with how you are implementing it.
addendum:
You did this all while I was writing that long post.
The past has a lot of memories to hold onto; but, today is chock full of new adventures, and, the future shouts out, "The best is yet to come!" -- TerryC