Charlotte Celestine is a very pretty combo, but I don't like CC at all - I find it a bit hard to say,actually. I don't think
Charlotte Celestine needs a second middle name but if you wanted one, I'd go for something quite short and sweet, so it's not an overly complex name alltogether. How about:
Charlotte Celestine MayCharlotte Celestine HopeCharlotte Celestine KateCharlotte Celestine MaryCharlotte Celestine AnnaCharlotte Celestine Rose
Bennet is not really my style; I just don't like surnames as first names. I would pair is with a solid, classic masculine middle name. How about:
Bennet
AlexanderBennet
ChristopherBennet
JamesBennet
JosephBennet
LukeBennet
Daniel