Ээээ... вообщета Роулинг взяла имя оттуда же. Буквально.

http://www.accio-quote.org/articles/1999/1099-connectiontransc2.htm#p3

Lydon, Christopher. J.K. Rowling interview transcript, The Connection (WBUR Radio), 12 October, 1999

"Lydon: Hermione Granger?"

"JKR: yeah, Hermione apea- yes, people will want to know how to pronounce Hermione, I get asked that so much, because a lot of people say 'Her-me-won,' which I think is really - [Lydon laughs] - I think it's really cute. I wish I'd told people right in the beginning it was pronounced Her-me-won. Hermione is a Shakespearean name - I - I consciously set out to choose a - a fairly unusual name for Hermione, because I didn't want a lot of fairly hard-working little girls to be teased if ever the book was published, because she is a very recognisable type - to which I belonged, when I was young .."