I have cousins who both have a grandaughter named Kirsty. Their oldest sister was Margaret, and so was their first cousin.
Researching my family tree, I found out that my great great grandmas neices and nephews were all called either Elizabeth, James, Allan, George, Mary ,Margaret , Janet, Robert, Thomas, Anne, John. or William. So they were all first cousins to each other. There was one Charlotte, born in 1824, and she must have felt left out! If someone had yelled any one of those names at a family gathering, up to 6 children and one adult would have answered.
Call your daughter Charlotte by all means. There is no copyright on names, and your friend might end up having all boys, or even no children at all.