The one actor who seems totally unfazed by Day-Lewis’s reputation is 10-year-old Dillon Freasier, a calm, poker-faced local boy with no professional experience. He’s playing Day-Lewis’s son, and the two seem to have developed the easy, playful rapport of co-conspirators. Dillon’s parents (his father is a Texas Ranger) had never heard of the Oscar-winning actor, had no interest in Hollywood and figured they’d better do some research before allowing their kid to mix with movie people. So they rented “Gangs of New York.” Big mistake. There was no way they were going to let their son work with Bill the Butcher. The producers were panicked, but they found a solution. A DVD of “The Age of Innocence” was rushed over to the Freasier household. Dillon got the job.