Ramona's cute and fun. It's so strongly associated with Ramona Quimby that I wouldn't use it for that reason, but it is cute anyway, maybe at least partially because of the character, who was cute even when she was obnoxious.
Her middle name in the books was Geraldine; I absolutely would not use that!
Ramona Brooke
Ramona Allison
Ramona Louise
Ramona Paige
Ramona Suzanne
As for a brother, how about Benjamin?
Before you criticize a man, walk a mile in his shoes. That way, when you criticize him, you're a mile away and you have his shoes!
Steve Martin