They are finally have entered the later spectrum of teenagerhood.
Dawn should get into vocational course in sports where she aspires to be a famous football (soccer) player.
Ricky should be getting into college into the world of science. He works and focusses hard so he can succeed as series progresses.
Dicky turns out to become a slacker. Does not much, just hanging with 'chicks'. He does try getting into most jobs but he's always shown getting fired all the time.
Nicky should aspire to become a chef. So he starts to employ himself to grocery shops to café upscaling to running a restaurant as series progresses. He will finally achieve to become a manager of a restaurant.