Hum, if you're planning to have Skeletons, Skeleton warriors and Grave guards, may I propose you to use those models as the Warriors, and those as the Grave Guards.

Simply because the first ones (current grave guards figures) really look like dead soldiers (actually, dead bretonnians knights), while the old Wight figures (second pic) have more of a grave guards "feeling". They're not simply dead soldiers raised to serve a new lord, but they have their own (undead-ish) equipement.
That would mean getting rid of the Wight unit, but from what I understood, Wight describe all kinds of not-totally-braindead-skeleton (and thus, include Grave Guards and Black Knights, aswell as the now discontinued Skeleton characters)

Overall, I think leaving out non- Blood Dragon Vampires themselves is a pity. I don't know what is the smallest unit size possible in MTW2, but wouldn't it be possible to have squads of like, 4 or 8 Lamhian, Strigoi or Nercrach vampires ? Yeah, that would be overpowered, but one could say they're newly born vampires, and give them a huge upkeep.