Three questions

Just finished the movie, and I was wondering about three things:

1) Why is Daxus titled Vice-Cardinal, and his domicile the "arch-ministry", when his role has nothing to do with religion?

2) What are the "Blood Chinois"? Was it ever explained just what they were, if neither humans nor hemophages?

3) The hemophages are sometimes referred to as vampires and (some?) are even equipped with fangs. What is the point of this, since they show no bloodlust?