pink hair on the left is astolfo from fate/grand order
pink hair on the right is hime arikawa from himegoto
brown hair on the top is saki mizushima from idolmaster sidem
brown hair on the right is chihiro fujisaki from danganronpa
blue hair on the bottom is hacka doll no.3

kid on the first panel is shinichi kudo/conan edogawa from detective conan

and yes, everyone except the kid is a trap in case you haven't figured it out.

There's only one way to figure out the culprit. Everybody, pants off!