I have to ask, in regards to Necromancy; there are the Korriban Zombies. Now, if I recall and understand it, the Alchemist can embue the bodies with the Dark Side of the Force; essentially making them an expendable vassal. A similiar case use was used by Dathaka Grash (sp?) long after his death. Bear with me, memory is fuzzy on this, to protect his crystal of Heart of Grash there was a ritual or protection spell placed upon it that brought the countless bodies/spirits of the dead back to life to protect it from treasure hunters or upcoming Sith.
But, the closest thing to Necromancy are the Korriban Zombies, and I believe the origins of this practice still remain unknown. Of course Necromancy is very vague in Sorcerery. Course, now that I think about it, it is largely binding the spirit/soul to an object or being. I guess to maybe disdain the confusion I'd would suggest changing the name of Necromancy to Binding? If that would help at all? That basically is much of the practice, with as much as I've looked into it.
Course if you ever do plan on unleashing this into a full blown guide, I can offer help as well, if you only knew the amount of hours I've spent researching every odd and in with Sorcery/Alchemy.
This is all correct, but as far as Sith Sorcery is concerned, necromancy deals with the manipulation and binding of spirits and Force Ghosts, like you said. I took the names of each facet from the wookieepedia page, since I felt that would create the least amount of confusion.
Korriban Zombies were created by the man you mentioned, through a mix of Alchemy and Sorcery, but the actual reanimation of the body would fall under Twisting Life. I left this feat out of the paragraph since I did not feel it was in the same league as the others mentioned, and believed people could always go to the wookieepedia page to read it more in depthly themselves. But I will edit the post in a bit to include the information.