Depp in the costume ball still looks really ... Byronic. Which could be a tacit nod to where it all began, with Dr Polidori's fantasy scenario about Lord "Ruthven" (aka Byron) and swooning over the prospect of having the life sucked out of him by this dark haired vampire beauty (male).
It's not clear to me from the material that has been released whether Barnabas gets encoffined in the 1770s, or in the more usual 1790s. The look in that still doesn't really work for the 1770s but could just work for 1795 or thereabouts. At least that is how I see it.
Of course 18th century men could be notorious dandies complete with face powder, "black patches" (beauty marks), etc. If Depp does a flashback sequence, his Barnabas in situ might wind up looking like Countess Natalie du Pres as portrayed by our beloved Grayson. lol
cheers, G.