I suspect this is a matter of two beings, Mr. Oliver (Earthmover) and Marmee Noir (Mother of All Darkness) who are both so old and have histories so filled with lore and mystery that no one can be truly sure which is older or more powerful. There is also the possibility that each developed their own vampiric strains uniquely and separately.
Since both of them predate all other vampires by a significant amount of time, in the case of Mr. Oliver, it could be a span of milennia, it would be difficult for anyone who became a vampire after them (even if they had a significant amount of time to spend) to know anything about their previous history unless Mr. Oliver or Marmee Noir chose to share it.
Since the origins of a vampire can sometimes tell something about its powers, strengths and weaknesses, most vampires are going to be loathe to reveal their origins or any useful information which could give a clue to their potential weaknesses. It is possible any misinformation on either candidate could have actually have originated with them, as a form of protective misinformation.
Since it appears Marmee Noir was both a vampire and a lycanthrope it is possible she may have been involved in the development of both groups, acting literally as a mother establishing codes of behavior. This might give her greater social status than the Earthmover who was inclined to spend a great deal of his time alone given his disposition as the last of his species.
Marmee Noir: Generally known as The Sweet Dark or as the Mother Of All Darkness (in Cerulean Sins, Anita dubbed her "Mommie Dearest"), Marmee Noir is the leader of all vampires and the head of the Vampire Council. She is both a vampire and a lycanthrope at once, and is apparently a were-cave lion.
- If she is to be considered a member of the cave-lion species which existed and became extinct in the Pleistocene epoch, from as far back as two million years old and they were believed extinct during the last ice age approximately 11,000 years ago.
According to several of the vampires, she was the first vampire, which means that, like Mr Oliver, she predates the evolution of homo sapiens. However, it has also been hinted that she is the Mother vampire in a metaphorical, rather than literal sense, having created the rules and culture that governs the vampire race.
It has been suggested that she is a unique type of vampire, distinctly different and more powerful, from all later descendents; perhaps not even a vampire, per se, but a unique type of monster with vampiric traits. Her powers include control over several species of vampire/lycanthrope mixes, the ability to project her attention and mental powers, and a deep control over darkness. -- Wikipedia > The Vampire Council of the Anita Black Series
