Charlotte's future husband, if she has one, is likely not getting a dukedom at all - since they are the highest-ranking hereditary titles, they have only been handed out to princes in over 100 years. One was offered to Winston Churchill after WWII, but that was an exception. The only way that it may happen with Charlotte's husband is if she becomes the heir to the throne. Otherwise, if he gets a title, it'd likely be an earldom.
Prince Edward has taken over a lot of his father's duties, including much of those dealing with the Duke of Edinburgh's Award, so I think the family, Charles incl