There is also a Harry Potter connection! From one novelist to another ...
How is Cedric pronounced in the US? I'm sure that the English actor you cite, Sir Cedric Hardwicke, pronounced it SEEDric; here in South Africa I've only known one, and he was SEDric, as I'd have expected. And, thinking of pronunciation, Cedric sounds a whole lot better than Cerdic, which would be close to Sir Dick in modern English, and most unfortunate.