Yes, its like how sergeant is a higher rank than corporal in military ranks.
duke
No - William is taller than his father. The Prince of Wales is next in line to the throne followed by the Duke of Cambridge.
the grand duke
Prince William has not lost his title as prince. The duke of york still retains his title as prince Andrew however it is common for the queen to give other titles to royal members when they marry. When William married Catherine she automatically receives the title princess William but they will be officially known as the duke and duchess of Cambridge. Also a duke is higher than a prince.
Prince Phillip is Duke of Edinburgh
Prince George, Duke of Kent
Neither, once a prince he can only be king. Actually, a duke is higher in Nobility Rank than a Prince. A prince's title does not change because he marries, however, once he marries, he is usually awarded a dukedom for his parents (King/Queen). As the ruler of this dukedom, he then becomes a duke. An Earl refers to chieftains set to rule a territory in a king's stead.
He is a duke, and a prince, as well as a few other things. But no royal ever goes by a name like 'Prince Duke Earl Charles". Instead, the person picks one title to be known by. Most people will choose the highest they have, and hence he's called Prince Charles. But as an opposing example, his wife, Camilla Parker Bowles, goes by the title of the Duchess of Cornwall, rather than a higher title she owns, Princess of Wales.
A Prince of Cumberland would be a prince who is the son of a prince who is Duke of Cumberland. For example, Prince George of Cumberland when his father, The Prince Ernest Augustus, was The Duke of Cumberland.
HRH Prince William of Wales Duke of Cambridge Earl of Strathearn Baron of Carrickfergus He goes by: William, Duke of Cambridge or Prince William
Yes he is the Duke of Rothesay and Cornwall
Prince Edward, Duke of York Princess Elizabeth Prince William Henry, Duke of Gloucester Prince Henry, Duke of Cumberland Princess Louisa Prince Frederick Caroline Matilda, Queen of Denmark and Norway