In which TV series is Ryan Atwood a main character?

In which TV series is Michael Bluth a main character? Who played Tobias Fünke in 'Arrested Development'? Who played Gob Bluth in 'Arrested Development'? Who played Ryan Atwood in 'The O.C.'? Who played Seth Cohen in 'The O.C.'? Who played Marissa Cooper in 'The O.C.'? Who played Charlie Harper in 'Two and a Half Men'? Who played Alan Harper in 'Two and a Half Men'?