So I almost made Daggerfall vampires before- possibly as an expansion to my Morrowind vampires... Almost in the past, but certain issues came up.

http://www.uesp.net/wiki/Daggerfall:Vampirism The Garlythi, Haarvenu, Khulariu, Selenu... They all have abilities that are fairly easy to replicate in Skyrim's engine.

the Anthotis would have more bonus magicka than the Aundae do, the Garlythi though physically not nearly as strong would be even tougher than the Quarra vampires, and have a once a day shield spell/damage reduction ability, the Haarvenu would get unique destruction Ice Storm/Wildfire spells, the Khulari would have a paralysis spell and lots of paralysis enchanted weaponry, the and Selenu would be the most resistant to elemental damage... All very very very simple.

But some of the abilities gave me problems. How would I make a silence spell for the Lyrezi? And how on earth would I make a free action spell for the Montalion or at LEAST try to replicate it as best as I can? And the Vraeseth, how would I try to replicate them having a nimbleness spell? And how would I make that distinctively different from "free action"?

And how would I make the Thrafey's healing ability meaningful or especially useful to vampires in particular- seeing as how vanilla vampires can heal themselves? Do I just make it an extra powerful heal? What are the best ways you can think of to get around some of these problems?

Any advice would be greatly appreciated... Although I do fear, that trying to meaningfully bring back these types of vampires, might be going against hardcoded Skyrim mechanics.

You could make a spell that drains/damages magicka and magicka regen as a sort of substitute for Silence. Nimbleness was just a Fortify Agility spell, IIRC; the closest parallel would probably be stamina regen.

As for free action, it's pretty hard for the player to get paralyzed in the first place - perhaps something that provided resistance against getting staggered, slowed (through Frost magic), disarmed, and/or Fus Ro Dah'd?

For the Thrafey's healing, maybe a Greater Power that restores all of their health once a day?