okay so some people don't understand... Uliana is Ursula's little sister, Uliana is the same person as Morgana from the little mermaid 2 she's named both Morgana and Uliana but in Descendants the rise of red they used Uliana instead of Morgana so people won't confuse her and Morgie's mom, morgana le fey/fay (the enemy of Merlin)
I have to stop you 15 seconds in. This is not the descendants franchise you are summarizing you are just summarizing The Descendants movies and one TV show The Descendants franchise includes not only the movies but the books, TV show, and the side videos that are included (Audrey's spa day and under the sea). These other pieces of media are important and relevant to The Descendants timeline the books and the movies do conflict a little bit but it is still necessary when talking about the franchise as a whole