1) Skellies are sort of the middle choice for
VC armies. They're not as easy to raise back, or as cheap, as Zombies, but they are more durable and will, on occasion, kill something. A pretty good unit, for
VC Core anyway.
2) Crypt Horrors are great. They're tough and durable, and can be raised back relatively easily, which is a real headache for your opponent. They're also a fairly strong combat unit too, and will deal out a fair amount of damage. Awesome unit.
3) Spirit Hosts are awesome too as they're cheap, ethereal chaff, with M6. Which is just brilliant. A real headache for your opponent.
4) Fell Bats are pretty good as they're cheap and fast so make very good chaff and can be used to hunt war machines in a pinch. Bat Swarms die pretty easily but the
ASL debuff is fantastic. Never really used them though, so I can't say how easy it is in practice to make use of it.
5) Coven Throne is meh. If you could take it without a Vamp Lord then it'd be ok, as the Throne itself has some good perks. As it is, however, it's just a cannon target for an expensive character, so really isn't that great.
6) These guys are pretty good, though I always find them hard to fit in. Ethereal characters are great, as they can roam alone or with a unit as they see fit and they can add some punch to units such as Skeletons. However, I always feel myself wanting to spend the points on a unit of Fell Bats and/or Spirit Hosts instead.
7) Interesting unit. It's tough to kill and can get some decent bonuses but I think it's just too expensive for something that will do relatively little damage. What makes it worse is that it's in a crowded rare section, a section that's often immediately filled by double Terrorgeist or Dual Engines. Perhaps it'd be better in Special. Worth trying out, but don't expect too much!
Hope this helps!