I love both Remusn and Regulus. I agree that people will probably often associate it to
Harry Potter, but I don't think it's a bad thing because the character is so incredibly awesome that I haven't even heard of anyone who doesn't like him :-) Regulus is very cool and interesting, too. I'd use either of these names anytime.
Urania is nice, too. I've nver cared much about the sound of it (probably because it makes me think of the word "urine"...), but I love the Muse association. It's definitely not a bad name, though.