As far as I know an adjective can be before noun(for ex. 美しい花) or before other adjective, but with て(for ex. 寂しくて眠れない夜). But in the following sentence「指定席みたいなコジンマリとした少年 」- this part is a bit of odd. Of course maybe I'm just don't know something, so can you please explain this part to me?
格好いいよりも可愛い路線で売っていきたいアイドル集団の末席が指定席みたいなコジンマリとした少年のような笑顔を向けてみた。
Thank you very much for help!