Hey there! It allows you to list more than one filename in the note tag, and the plugin will choose a random sound effect for that action. So in other words, it doesn't distinguish between what kind of skill was used, no.
For when the actor's HP reaches 0, another sound effect is not needed because it's already playing a sound effect for when the actor is getting hit, and it would negatively impact the get hit sound effect(s).
I hope this clears it up for you.