In thinking it over Rick was on till 2011. Because he was on when SB1070 passed. Brooke replaced him in 2011 after working on his shift. At some point her shift moved hours.
Brianna was basically added as anchor when Wolf quit a afternoon hour or two he did. She used to fill in for Brooke. Brianna Keilar, this idiot, was mostly a White House or Supreme Court reporter. But in 2006 to 2008 filled in a lot and by 2010 had a shift but was removed. CNN shifts never last too long and always make changes. She basically started at CNN as intern. But did spend two years elsewhere then returned. In 2006 when she joined was 25.