In one scene Poppy asks: "What is this place? Hogwarts?" Then the movie cuts to a scene with Matron (Shirley Henderson) who played Moaning Myrtle in the Harry Potter movies.
Harriet's quoting from the end of Pride and Prejudice shows that this film was written by Americans as it's from an alternate ending to that film that was added for US audiences, but did not appear in the UK version.
The dance the Abbey Mount girls perform before the last part of the lacrosse Finale is a modified Haka, or "Maori war cry", as used by the New Zealand All Blacks rugby team. The first New Zealand rugby team to play overseas back in the late 19th century was the first to perform the Haka before their matches against the Australian teams to intimidate them. The Girls' Haka contains several of the present day's All Blacks' more aggressive Haka; Standing with knees bend while holding their arms bend over each other and their hands fisted, sticking out their tongue while yelling at the other team, slapping their elbows, thighs and chests, kneeling on one knee with a fist in the ground and their threatening facial expressions.