Without any provided information regarding the plot, characters, or themes of the film 'Cindy Ann', a comprehensive evaluation of its portrayal of LGBTQ+ characters and themes cannot be conducted. Therefore, the net impact is categorized as N/A due to the absence of depictive content for analysis.

The 1960 animated short 'Watermelon Watcher' is a Tom and Jerry cartoon focused on slapstick comedy between a cat and mouse. It does not feature any identifiable transsexual characters or themes, nor does it engage with gender identity in any capacity.

The movie does not contain any action or adventure elements.

The film "Cindy Ann" (1960) does not appear to be an adaptation of pre-existing source material with established character genders. Without prior canon, it is not possible to identify a character whose gender was changed for this specific film.

The provided information for 'Cindy Ann' (1960) is limited to its title, year, and director. Without details on source material or specific characters' established races, it is not possible to identify any instance of a race swap.