My headcanons about the upcoming Descendants: Wicked Wonderland movie
Before the events: The Queen of Hearts and Maddox Hatter met at Merlin Academy, back when the Queen was still just Bridget, and became very close friends. This later led to Maddox becoming her trusted confidant once she became Queen, as well as a mentor figure for her daughter, Red.
Because of that, Red grew up around Maddox and naturally got to know his son, Max. In the original timeline, he was just a shy boy Red felt both fondness and a little pity for, while he secretly had feelings for her. Maddox was a brilliant but crazy inventor, the pocketwatch was one of his creations, after all. Max was his assistant, always hiding behind his father.
In the new timeline, however, Max is a completely different person from the one Red remembers, and Red also has a younger sister, Pink. The three of them used to play together all the time as kids. They were an inseparable trio, constantly getting into trouble and going on adventures all across Wonderland. Max eventually developed feelings for Red in this timeline as well. Maddox, of course, wasn’t only Red’s mentor, but Pink’s too.
After the events of Descendants: The Rise of Red: Red, Chloe, and Maddox are the only ones who still remember the previous timeline. Red and Chloe remember because they traveled through time and changed the course of events, while Maddox remembers because he invented the pocketwatch and is therefore able to perceive changes in the timeline itself.
Eventually, thanks to Maddox, Red realizes that the original timeline needs to be restored, so she sets off with Chloe to fix everything. However, Pink, Max, and all the other protagonists of Wicked Wonderland (Hazel Hook, Luis Madrigal, Robbie Hood, Felix Facilier, and the Smee twins) basically force themselves into the adventure too.
As they travel through time, they all gradually regain memories of the original timeline. Max especially begins remembering his old feelings for Red, and even his personality starts shifting back into the quieter, sweeter version of himself from the original timeline.
I’m not exactly sure how, but in the end they somehow manage to restore the original timeline while still preserving Pink’s existence, and then they all return to the present. By that point, Max has convinced himself that he never really had a chance with Red. But in the end, she falls in love with him too.
One day, Red and Max get married and become the Queen and King of Wonderland, much to the happiness of both Pink, who remains the best friend of both of them forever, and their proud parents.