I would check out some of the videos of the line actors they have at netherworld and other haunts on YouTube. I agree with Allen on this especially if your haunt has long lines creepy funny and lowbrow are easier to maintain for long periods of time and keep peoples attention and keep them entertained. Before you offer to do this a few questions I would ask are how quick are you verbally, Can you maintain a character with in the public eye for very long periods of time, and do you have any special talents that can be used to keep people entertained (Juggling, stilts, acrobatics, comedy, singing, general strange quirks). Your main job outside is just that keep peoples mind off the wait and help get them into the mood to be scared and to have fun. as for your costume I could not say much without knowing the theme of the haunt if the theme is vampires think more Renfield in nature.