NO, she's the disney retelling of Hans Christian Anderson's tale. In the original Hans Christian Anderson story the mermaid was nameless
And note that the original story was also a "story" - fiction. So the Mermaid could be played by anyone else - a black, chinese, white, whatever person
And Hans wrote the story himself, it's not based on Scandanavian legend
Disney's stories utterly changed the story of the little mermaid (Hans' story ain't happy) and the same for the Disneyfied Cinderella and Snow White.
You're picking nits, which are incorrect. Both Cinderella ( ALL of the versions! ) have happy endings as does Snow White. Disney cleaned up some bits and pieces, as they also did with SLEEPING BEAUTY ( which is the MOST gory and also contains two rapes resulting in two bastard children ), but these all have happy endings.
Disney ruins every children's story they have laid their hands on and NOT for the better.
The stupid race change in Mermaid is not quite as bad as what they did to THE FROG PRINCE ( from Europe to New Orleans AND making it an all b lack cast ? Good grief! ) but close.
No, just because something is fiction, does NOT mean that someone else can or should be able to change the race, sex, etc. of ANY story! Especially not when the story is at least a couple of 100 years old or many more older and well known world wide.