This is some explanations for the projects to give them some logic arguments:

The plot is plausible When Ariel and Ursula make the slave deal, the sea witch wants to make the princess her slave (the original plan). BUT when Ariel fights against Ursula in the wedding, she makes up her mind. Instead of enslaving the mermaid Ursula plans to kill her to punish her resistance and rebellion. But the witch is a bit tricky, and she needs to make suffer Triton with the guilty of her daughter death. So she possesses Triton body in order to force him to assassinate his proper daughter. Ariel becomes pregnant eight years later because she and Eric meet some difficulties to have children. The prince and the princess think that she is unfertile. The Queen is afraid of merpeople because they are from different species. Its a form a Racism. The Queen is so afraid that she can do some crazy things to not mix her blood. In the history the Queen is manipulate by a dangerous racist noble who wantq to separate the prince and that failure