Wow, Gothick! I had absolutely no idea all of this went into the placement of two words on a poster. I guess I am in the WRONG business.
Thank you for the insight. I may have to change careers now.
And michael c, your analysis of the original series and its billing is similar to what I concluded. The longer an actor was on continually, the higher billing he or she received. There were exceptions down the line, with Jonathan Frid, Grayson Hall, and David Selby all getting higher billings much more quickly than others, but over all, continuous time spent on the show meant a higher place in the credits with very few exceptions.
Joan Bennett, Jonathan Frid, and Alexandra Moltke all got special billing in the original. (Note how later Victorias never received the same billing as Moltke.) And I hope that the roles they made famous will be treated with the same respect in terms of final billing for this film. We know Depp's status as Barnabas, but it will be interesting to see how Pfeiffer and Heathcote will be billed in terms of special wording.