OK, but what happens then to the feruchemists that the lord ruler catches? It always says that the keepers must remain in hiding, but what happens when they do, and like I said, perhaps it's only one feruchmist, still, I admit, it's a stretch but remember, there's only like 20 inquisitors in the entire empire, is it such a stretch that the lord ruler couldn't have caught at least 20, in the past 100 or so years, (or more, Inquisitors are longm lived, remember). As for mistborn, I'm sure he could find 20. I admit my theory is still weak in some places, but If they just use mistings to get their powers, how can they burn atium, how do they heal so quickly? And I still am definately sticking to my Skaa theory, I'm sure they have to power to amplify allomancy.
And as for the inquisitors created at the conventicle, who says they are complete inquisitors, maybe they are just partial ones, like Zane. Maybe they just have the enhancement ability, from the Skaa slaves, and they are seeking to complete themselves, byt killing off the keeperes, and then dragging their bodies off with them for their hemalurgic rituals.