Disclaimer: I don't own Teen Wolf or Gravity Falls, everything belongs to their rightful owners.
The Boy
His name is Dipper Pines. He is the same height as Stiles and Scott but because his posture is a bit sagged he looks shorter then he really is. He carries around a big backpack with different books, non with subjects that belongs to what the school teaches. His hair is unkempt and hides under a brown lumberjack hat, to warm for the current weather.
He's quiet and only talks with his sister. He has the same classes as Scott and stiles, so they see more of him then they really want to. At gym class coach notice Dipper physics, because he may look weak but damn he probably could outrun Scott if he wanted to, and suddenly Dipper also got lacrosse practice with them. It's weird how faith pushes them together.
The Girl
Her name is Mabel Pines and she is the polar opposite of her brother. While Dipper is quiet and reserved she's loud and outgoing. It doesn't take long before she got her little gang of "outcast", in Lydia's opinion. That way they don't get a chance to talk with her, as she seems to never be alone.
She has long brown hair in a neatly made braid and always carries around a pack of brightly colored Band-Aids, both her hands and her legs are filled with scratches that hides behind each color. Mabel is similar to Stiles in that way she can't seem to sit still, her leg always bounces against the table, and she's always the first one up from the bench each time the teacher quits the lesson.