I really like it but I like pretty much any "Rose" name. I plan to suggest Rosalie if I can't get my SO on board with just Rose or Rosa (that is to say if he vetoes my other top girls names) because I think Rosalie has a "younger" quality that appeals to more people.
And I think Rosalie fits in fantastically with your other kids names. Scarlett and Rosalie sound especially poetic together