The Magic necklace keeps the main color of whomever uses it to transform into a mermaid. It keeps Merliah's pink in her top and tail and Kylie's purple, despite not being a natural mermaid.
It makes sense the ceremony allows Merliah to change between human and mermaid as she wishes. Both are her true self.
The Ambassadors come from different locations around the world: Renata is from somewhere in Africa, Mirabella is from Brazil, Selena is from Russia, and Kattrin is from South Korea. In the dolls, Kylie is the Australian ambassador for some reason.
In an attempt to heal the nation, on February 14, 2021, podcast hosts Richard Martin and Alexander "AJ" Jones of the Cult Popture Podcast released an 18+ hour comprehensive podcast reviewing the 37 Barbie films. The retrospective took over a month to prepare and features numerous guest speakers as well as an original song created specially for the podcast.