Audio commentary included with “Ant-Man and the Wasp: Quantumania” for release in the home media market (via directly), Peyton Reed noted that Cassie is 18 in the movie (making her about two years older than the Emma Fuhrmann iteration). Calling Kathryn Newton “an actor I’ve admired for a long time”, Reed explained that her main concern was to find someone for the role who “could really hang out with Paul Rudd and somehow not end up in the dust”. Added:
“It should be sharp, fast and funny. Also, [Newton] is an athlete. He is a world class golfer. He has the physics for the role.”
In his defence, you don’t get the impression that Reed is deliberately trying to belittle Fuhrmann or suggesting that he can’t do such things. He seems excited to be working with Newton, an actor who has previously showcased his comedy chops in movies like “The Blockers” and especially Christopher Landon’s awesome body-swapping slasher horror-comedy. “Strange.” Newton’s comebacks as the moody teenage girls in the TV series “Halt and Catch Fire” and “Big Little Lies” also demonstrated her readiness to capture the more serious side of her teenage experience; an adult ID separate from your parents’.
Speaking to Reed about the audio commentary, “Quantumania” writer Jeff Loveness suggested that this was another factor that made Newton cast for the movie:
“And she’s just someone who can look like Scott Lang’s daughter. You know, what does she get from him? What does she stand up to? She has Scott’s heart. She also has a bit of that sense of humor, a bit of that messy quality.”