I currently started reading Bloodborn, first of the Ulrika the Vampire novels.
*SPOILER ALERT*
I dunno how canon it is, but Gabriela Von Nafthafen (sorry if I misspelled), who is Ulrika's blood-grandmother, noted that while Bloodlines define generally how a vampire will be (Lahmian being seductive, Von Carstein being ambitious, etc.) the life of the vampire before receiving the kiss will define him as much at their bloodline. So you may have mighty warriors from Lahmian blood or Sorcerous Von Carsteins, etc. if the human before being turned was predeposed to being so.
She also notes that very few vampire remains that get from just one bloodline. She explains that while Vampires do not breed, they can mate. And said mating can bring a child who may inherit from one or both parents.
Gabriela is has the blood of both a Von Carstein and Lahmian. She works for the Lahmians as an undercover agent in Sylvania, easily passing as a Von Carstein if needed be.
So hybrid Vampires can exist. Well as far as this Black Library novel says.