Just so we're on the same page...Here are the characters.

 Regina George is Jamie Lynn Spears

Jamie Lynn Spears - Yup, she has to be American. :P

The Nice Girl (Lizzie McGuire) is Aida Minefield

Aida Minefield's Home Life. She is from Greenwich Village. :P

Jerry The Girl is The Best Friend Miranda.

The Weird Girl (Dakota Fanning) is Tami Minefield. 

Her Home Life is Elle Fanning. Sometimes Kirsten Dunst.

The Girl-Next-Door is Katara or Kristen Stewart.

The Weird Guy (Nick Hornby) is Joan Roderick.

Eternal Sunshine of the Spotless Mind.

The Stud Bum (The Guy Who Smokes) is Teddy Krakow or Jared Leto