Well, if you can find the npc's script_targetname, you'd only need to change one script per map. But yeah, a little too much work. Coding is prolly the only way.
Must be a way to do it. Coding of course, is the obvious answer but what one exactly, right? Perhaps, since an NPC spawn can be randomized, a bit of that can be spliced into randomizing also, the parts? Just a thought, I could be, and probably am horribly wrong..!