unless you have ragdoll they wont die like the stock characters i guess - probably best if they dont anyway to be honest if they dont have the same structure, not sure how it'd handle it, though it might be fine.
not sure if the setting in the fpe alone is enough, might need some animer conversion or something maybe - pretty clueless on modelling side of things im afraid.
as for your own death animations well you can definitely do that but good luck getting it to run as once an entity reaches 0 hp the script should stop running which from my experience means they wont animate the death
life's one big game
windows vista ultimate
i5 @3.3ghz, 4gb ram, geforce gtx460, directx 11