No, they are not.
My sister, Eve Kosofsky Sedgwick, the professor of English literature, writer, critic, and poet who sadly passed away a few days ago (April 12, 2009), acquired her last name...
No Kyra Sedgwick was not in Twilight the movie although she looks like the actress that played Esme (Edward's mom). She's not and to make sure look up Twilight and click on the cast to see names.