An interesting point about Barnabas' comedic dialogue in the film is that the idea of it may actually be traceable back to DC. I was looking over some stuff from the '04 pilot the other day and I suddenly remembered a remark that DC made that because Willie was going to be closer to the original series' characterization should the pilot go to series, the humorous touches in the WB series (because apparently DC came to believe there had to humor to offset "all the biting and tearing") would be coming mostly from Barnabas coping with the modern world. And if that truly was the plan, well, they've simply picked up on it for the film.
I also remember that back in January '08 Jim Pierson remarked in an article on the MPI Web site about how Barnabas coping with the modern world be featured in the film and it was something they had planned to do had the '04 pilot gone to series. And while he didn't use the word "funny," he did imply that there would be humor to it in the film. But I seem to recall that the first time the word "funny" was used was when Richard Zanuck used it in May '10, which not incidentally was before Seth Grahame-Smith became involved with the film (he wasn't brought on board until July), so that definitely proves that the film was intended to have humor even when the script was being written by John August.
72 days 9 hours 47 minutes 40 seconds until the day the Depp/Burton Dark Shadows is released(ET)!!