I've never read/seen Twilight, so my mind wouldn't go there at all. For me,
Rosalie is just a beautiful and classy name with a sparkle about it. I love it. :)
Rosie is a great nickname.
Love it so much that even my ex-fiance hasn't ruined it for me. :P
Rosalie has enough usage outside of Twilight that I think you're fine. Renesmee is a different story.