Which name belongs to both a Dick Tracy villain and a type of crew cut?

What is a devoted follower of Jerry Garcia's band called? Which dialect is associated with the East End of London? Which dialect of southern France is named after a region? A dialyzer is an artificial version of which organ? Complete the title of the Charles Dickens novel: "___ and Son". Which dictator was known as "Il Duce"? What is a diplomatic emissary of the highest rank called? Which word names both a diplomatic official and a type of briefcase?