So here's the problem. The British royalty being connected to the Saxe-Coburg Gotha line didn't begin until Edward VII, who was the son of Queen Victoria and Prince Albert of the Saxe-Coburg family. Edward would begin his time as monarch in 1901. Conversely, Dracula, the Bram Stoker book, was published in 1897 and had been a project he had been working on for the better part of a decade, largely because of his study of Transylvanian folklore that informed the novel. Romanian culture featured a vampiric creature called the Strigoi, upon which Stoker's version of Dracula is based, likely with a bit of Vlad the Impaler thrown in for good measure.