Would you immediately think Kate and William or would you just think lovely name?
I have a tendancy to call my children by first and middle name together as think why have a middle name if you don't use it.
If so any other middle names you can suggest as don't want to use a family name, I like my child to be an individual not named after somebody. Another name I liked when pregnant with my son was Jacob. So another option would be Louis Jacob.
Thanks!