I have a great Aunt
Rosalie, so that was my first thought. No one calls her
Rosie. She's
Rosalie to everyone.
I don't think it's arrogant at all. I think it's wonderful.
The Twilight connection will fade. (As long as you don't give
Rosalie siblings named
Alice and
Jasper!)
I think
Rosalie is a beautiful classic name. I'd use
Rosa as a nn before
Rosie. I call all of my children by their full first names, though, so I may not be the best person to answer that one.