(New post to avoid more edit ninja shenanigans).

*Facepalm* Right, so that's an important one then.

Actually, I'm not sure about the holy water. The main exception is taking damage in the first place, but it doesn't specify lethal damage. So, it takes *damage* from the holy water, which is then converted to nonlethal by the regeneration, and ignored by the dead nerves. Could work.