I don't think Charlotte has dark blonde hair, to me, looks like light brown hair, she never had blonde hair (light or dark) on my opinion. Her eyes are the same as my cousin's dark blue/blue-ish gray eyes, very pretty!!! I'm still intrigued about George's brown eyes, he has a father with blue eyes and a mother with dark blue/blue-ish grey eyes, genes are a very mysterious and fascinating thing (I think the same happened with the Spanish royal family, Felipe has blue eyes and Letizia has green eyes, though Infanta Sofia was born with brown eyes).
Lets see about Louis, hair is very unpredictable at this stage, my friend's baby was born with black hair and then it fell, and it grew gold blonde, so who knows what hair color he will have...but as for the eyes, I think it will be like Charlotte's. It would be great if he had crystal clear blue eyes, each child would have their own set of eyes in this cute little family (not so little anymore
)