When it comes to character backgrounds, it seems that Fate: The Winx Saga merely took inspiration from Winx Club versus sticking strictly to the source material. From what we see in the live-action series, Aisha is no longer a quiet, reserved crown princess of Andros. Instead, she grew up as an athlete with friends versus being isolated by her parents as a child. She's also a core member of the "Winx Club" right away rather than joining later, like her animated counterpart. In addition to the whitewashing of Musa—which fans have angrily pointed out since the casting was announced—she is no longer the fairy of music. Musa is now a fairy of "the mind," also known as an empath, who can feel other's emotions and take on what they are feeling. She does still have a love of music, however, we don't know if she is naturally gifted when it comes to music like she is in the cartoon.
Not only is Sky no longer a prince on Fate: The Winx Saga, he's led to believe that his father was killed in battle and is the ex-boyfriend of Stella. Winx Club has him as the prince of Eraklyon and also saw Sky trade places with a squire named Brandon, who becomes romantically involved with Stella, so that he can live a normal life.