Costuming

 Milly's color palette would consist of pink, brown, white, beige, etc. She is very bubbly, so her style will match that by adding many rounder shapes, frills, and a soft silhouette. The things I think of when it comes to Milly are boats, ribbons, bubbles (surprisingly), and soft makeup.

Cleo's style is a little more streetwear, not as cute as Milly's. When I think of her, I immediately think of gold jewelry, a very earthy style. Her color palette is brown, green, navy blue, and yellow. Cleo's earthy style translates into lots of different layers, great jewelry, and very flowy. Her style is a bit calmer than the rest of the group, and her jewelry and uniqueness make her stand out.

Theo is a pretty clean-cut guy. His color palette would be blue, green, beige, etc. His style feels very strict or restricted in a way, showing his quiet and closed-off personality. Since he's a nerd, he will obviously have glasses. He would also most likely be wearing some kind of dress pants or khakis. This would then be topped off with a slick hairstyle.

The last character (who was originally named Cary, now named Joaquin) is the delinquent type. Joaquin is definitely punk or grunge, which would mean their color palette is mostly black, with some hints of red, blue, and grey. Essentially, their style would mirror Milly's. They would have a much sharper silhouette.