using ApplySpell to add a new innate ability to a character?

amika

I have a custom innate ability added to an NPC; a script detects if she has a certain item equipped, then it uses ApplySpell to apply a spell similar to the one that gives the PC the slayer change ability to add the target spell to her list. when the item is unequipped, it's removed.

I noticed you have to refer to a spell by its .spl filename if it's going to be part of a "give spell" spell effect, which isn't ideal for installing multiple mods... Is there another way to have a spell added to a character's innate list via script, or a way to have WeiDU force a spell to have a certain unique filename while still being properly referenced in spell.ids? Do I even need to worry about having it in spell.ids if it's an innate ability only one NPC is ever going to have/could I rely on what I set using DLTCEP/could I do ADD_SPELL by hand in WeiDU using COPY and APPEND?

EDIT: Just using 'copy' to put the spell in my override folder seems to be enough; I'm handling all the !HaveSpell checks and RemoveSpell actions with variables and ... more spells. Is this a terrible idea that will break things down the road?