In which film is Ennis Del Mar a character?

In which film is Harry Burns a character? Who played Sally Albright in 'When Harry Met Sally...'? Who played Annie Wilkes in 'Misery'? Who played Ennis Del Mar in 'Brokeback Mountain'? Who played Jack Twist in 'Brokeback Mountain'? Who played Louis Bloom in 'Nightcrawler'? In which film is Louis Bloom a character? Who played Ryan Stone in 'Gravity'?