SOSOSOSOSO sorry it took so long for me to comment, I still have to read through the rest of the comics. |D
ANYWAY Whedon-pires are pretty much your basic vampires (HAVE A HANDY WIKI LINK! PS I love fandom wikis they are so much obsessively detailed awesomesauce). The idea's basically that: -Vampire bites you -You drink vampire's blood -Demon parasite-thing kicks your soul out, takes up residence in your body and has lots of bloody fun-times for eternity
And they're susceptible to all the classic vampire-y stuff -- wooden stakes, beheading, sunlight, fire, garlic, crosses, holy water, not being invited into private places, non-reflective-ness, etc. They look normal during . . . well normal times, and then get bumpy, yellow-orange eye-y, fangy when the blood-lust sets in.
BUT YEAH. It sounds like the reason vampires came back after being banishedwtfever (is that really what they did at the end of the series? Or was that something they implied happened later on? 'Cause I thought the point of the series finale was just that they closed the Hellmouth and, um, destroyed Sunnydale 'cause Angel kept going after that >.>) COULD have something to do with the whole widespread mutations. Thing. So you could use that as an excuse to futz around a little with his powers/weaknesses and give him a little more mobility than just coming out at night without just sending him to Gotham, land of perpetual sunset? XD
ALSO ALSO like I mentioned to Lina, since we have canon!vampires/zombies/demons I see no reason why we couldn't have vampires too. Especially in a city that I'm not sure was ever really visited in canon. |Da