Reanimation Question

[Hellboy]

Here is a very basic, noobish reanimation question (I did try the manual and searching, but no luck on the precise answer).

I've got a Mound Fiend hanging around for a not particularly undead kind of nation. My question is, whether it's worthwhile to use him for reanimation, in order to pick some zero cost chaff. More specifically, he can reaninmate ghouls, longdead or soulless. IIRC, in tips I've seen that if I reanimate ghouls that'll reduce population, so that seems like a bad idea - or is it?

OTOH, in most of my provinces I've got no corpses, will that place a limitation on how many soulless and/or longdead he can reanimate?

Finally, does the Sword of Justice raise his priest level for the purposes of reanimate?

TIA,

Hellboy