There is no end, it seems, to the inventiveness of J.K. Rowling when it comes to naming her characters, and sometimes you think she's doing it as a private joke, for her own amusement and for that of any adult reader who might happen to catch the reference.
Many of her characters are named for, or have names alluding to, characters from the history of literature. Argus Filch's cat Mrs Norris is named after the truly dreadful sniffy mean-spirited aunt in Austen's Mansfield Park. Professor McGonagall is named after the poet widely known as the worst poet evah, a Scot called William McGonagall who had no ear and no sense of metaphor but was extraordinarily prolific and remains loved by the Scots (including Billy Connolly) for the hilariousness of the sheer awfulness of his verse, 'so giftedly bad he backed unwittingly into genius'.
But for sheer obscurity and light-relief game-playing in the now very dark Potter story, Rowling has raised her own bar once more with the extremely minor character called Reg Cattermole who turns up in the new book. 'Reg' and 'Cattermole' are the given name and surname respectively of a couple of unfortunate undergraduates who eventually get together romantically in one of the more minor sub-plots of Dorothy L. Sayers' masterpiece* Gaudy Night**.
* Well, I think it is.
** A book that Tolkien hated. Which is telling in itself, really.