answer:As I understand it: (1) Your second paragraph is spot on. (2) Camilla holds the title of Princess of Wales, but she uses the title Duchess of Cornwall out of respect for the dearly-held memory of Princess Diana. (3) Duchess is the female royal rank just below the monarch. (4) There is not binding precedent for what royal title Kate will take when she marries William – however, when William’s uncles married they took the titles of Dukes, and their wives Duchesses. When (and if) Charles ascends to the throne, it is likely that William will take the title of Prince of Wales and Kate will then be Princess as Wales (considering the generation gap and how William reminds the people so much of his mother, the passing of the title in a public sense will most likely be a moment of healing rather than contention). I think that’s everything…