I just read the story you linked to and like it quite a lot - I'm surprised you haven't explored that already because these two stories seem so rich with possibilities. The contrast of the old man and Faith was very well-done. Faith's got as many daddy/parent issues as Buffy does. I think it works better than if it had been Buffy in that circumstance, as you've written it. And I'm still fascinated by the "Slayer lineage", and the idea that Buffy is Kendra's "sire" and Faith's "Grandsire", to use the terms used to refer to the Fanged Four, although that isn't spoken of as such on the show. (And of course, the new Slayers have two mommies (plus a lesbian midwife)...but I digress.)

Zabuto basically being an OC is probably a good thing because it gives you plenty of room to play. So yes, consider this a request to write more about Zabuto's world, if your brain takes requests.