Summer Days with Coo does not feature any identifiable LGBTQ+ characters or themes. The narrative primarily focuses on environmental issues, the friendship between a boy and a mythical creature, and family dynamics, without incorporating queer identities or experiences.

The film "Summer Days with Coo" centers on a boy's discovery of a kappa and their subsequent adventures, exploring themes of family, environmentalism, and societal integration. The narrative does not feature any identifiable transsexual characters or themes.

The movie does not contain any action or adventure elements.

Summer Days with Coo is an original animated film and not an adaptation of existing material, a reboot, or a biopic. All characters are new creations for this specific film, meaning there is no prior canon from which a character's gender could have been swapped.

The film features original characters created for this specific animated movie. There are no instances of characters with a previously established race being portrayed as a different race.