So yesterday I tried to set myself a bit of a challenge which was inspired by a certain urist. I encountered several vanilla bugs which are brought to bear when trying to do a hermit challenge, but I also see they could apply to other circumstances.
First was that the local dungeon populous considers the crushing of grudges like they've lost a loved one. (6 cases of at least -20 unhappiness)
so you can't use that method at all.
Second arose when using the graveyard ghoul method. (ofc naked, but I saw that as an awesome extra challenge) The problem is that is when you have the ghoul master (couldn't be the graveyard ghoul, due to previously mentioned bug of him not going into military service), steward (and overlord? I didn't confirm it) set and they all die a tragic death without there being a valid successor, It bugs out the nobles screen permanently, all options vanish and as such you also can't set up any sort of military as those at default require even the most basic noble.
The third, not neccessarily a vanilla bug, was that the graveyard ghoul I got had all his exp gains bugged including ones he should by default get. Yes I did through my cheaty methods add a number off skill he shouldn't have had.
There is one other method I haven't tried for my challenge and that is the necromantic altar approach. but...yeah, that's going to need someone (a warlock?) alive by default.....isn't it?