No plot details or character information for the film "{蒸生瓜}" were provided. Therefore, an evaluation of its portrayal of LGBTQ+ characters and themes cannot be conducted, and no identifiable depictions are present based on the available data.

The film {三姑嫂(下集)} (1965) could not be evaluated for its portrayal of transsexual characters or themes due to a lack of specific plot or character information. Therefore, its net impact is rated as N/A.

The movie does not contain any action or adventure elements.

There is no evidence that "Steamed Melon" (1965) adapts characters from prior source material or history where their gender was canonically established as different from their on-screen portrayal. The film appears to feature original characters or common opera archetypes without gender alteration.

No source material, prior canon, or historical context is provided for the 1965 film "{蒸生瓜}" to establish any character's original race. Therefore, it is not possible to determine if a race swap occurred.