Hi and welcome!
I haven't read The Summoning so I'm going to be just offer advice based on what you typed here. In FFXIV, necromancers are unethical conjurors/white mages who do horrible things in defiance of death.
However, what you seem to be describing is a medium. The class/job most aligned with that concept could be thaumaturge because their concepts are based on the funerary practices of the priesthood of Nald/Thal.
Your werewolf boyfriend could be a marauder/warrior because that's a class associated with rage.
Liz could be any class because being dead happens to everyone.
Victoria and Simon could be any of the magic using classes. I'd pick summoner and red mage. Not, sure if a retainer could be a blue mage.
The big problem you are facing is that you'd need to level each of the classes you choose before you can assign them to your retainers. Secondly, no one would be able to see your retainers. So, you'd be RPing alone.
Just my two gil.