Once upon a time, which in this case means less than 10 years ago, Dove Cameron dreamed of dyeing her hair.  “When I was a kid, I always wanted to dye my hair crazy colors,” says Cameron. “I’d use Kool-Aid, whatever I could find. What I had decided I really wanted was sort of a light lavender.  “But when I became an actress, no one would let me change my hair color.”  No one, that is, until she landed the role of Mal, daughter of Kristin Chenoweth’s Maleficent in the new Disney Channel movie “Descendants,” which premieres Friday at 8 p.m.  As the daughter of a classic Disney film villain, Mal has attitude to spare, and one of the outward signs is that she has dyed her hair bright purple.  Disney. Making dreams come true.  “Descendants,” to no one’s surprise, ultimately follows an even more classic Disney tradition — setting up a nightmare and weaving it into a dream.  Mal is part of a teen posse that also includes Carlos (Cameron Boyce), son of Cruella de Vil (Wendy Raquel Robinson); Evie (Sofia Carson), daughter of the Evil Queen (Kathy Najimy) from “Snow White”; and Jay (Booboo Stewart), son of Jafar (Maz Jobrani).  They all live on the Isle of the Lost, a sealed-off land to which it turns out all Disney villains are eventually exiled.  As our story begins, the four teens are about to get a reprieve and be allowed to enter Auradon, the magical, sparkling-clean fantasy kingdom whose kingship is about to handed over to handsome teenage Prince Ben (Mitchell Hope), who’s pretty sparkling clean himself.  Casting aside the doubts of his father King Beast (Dan Payne) and mother, Queen Beauty (Keegan Connor), Ben declares the sins of the parents should not be held against the children.  But the four newcomers soon remind us that you don’t spend your life being raised by a supervillain and not have some devious tricks in your DNA. Specifically, Maleficent instructs Mal and the others to steal the Fairy Godmother’s magic wand, with which the adult villains could seize power again.  It’s a classic superhero/supervillain showdown, done Disney style with a lot of song and dance.  “When they approached me about this project, I immediately knew I wanted in,” says Kenny Ortega, who choreographed and directed. “It was only after I’d accepted that I started to have some concerns.  “These are such heritage characters that I started to realize how much pressure there would be to get them right and get the story right.”  Cameron may be only 19, and the original “Snow White” may have been released 78 years ago, but yeah, she says, she knows these characters as well as if they were all on Instagram and Snapchat.  “I grew up with them,” she says. “I loved them. How could anyone not love this stuff?”  So it took a while to wrestle them all into a story that kept the villainy, but was also modern, breezy, hip, humorous and musical.  “The original concept didn’t have music,” says Ortega. “When we decided to add it, we just tweaked the story a little and it fit seamlessly. My rule with music is that it shouldn’t just be there. It needs to move the story forward.”  The 65-year-old Ortega, who learned at the elbow of dance giants like Gene Kelly, has built a towering reputation over the years as the choreographer for the likes of Michael Jackson and the movie “Dirty Dancing.”  So he knows how to do grownup dance. But he’s also choreographed all of Disney’s “High School Musical” movies, among others, and he says he has no trouble creating for a family audience.  “I’ve never had anyone censor or change anything I put in a Disney movie,” he says. “I’ve been working here all my career and I know what it is they want.  “If anything, I have to push myself in the opposite direction, keeping in mind this is a family and youth story.”  “Descendants” also may create an interesting career juncture for Cameron, who is best known for playing both lead characters in the hit Disney series “Liv & Maddie.”  While Mal is still a Disney character, she’s in a more adult situation, facing decisions like whether her loyalty to her mother should lead her to take an action that could destroy a kingdom.  In fact, says Cameron, that’s one of the many things she likes about Mal — that she gets pulled in a hundred directions.  “She’s crazy complex,” says Cameron, and that’s a big part of the reason Cameron sees her as fully relatable despite her unusual family background.  “Your average teenager can’t relate to a girl who casts magic spells,” says Cameron. “But she does understand someone who is torn about her upbringing and the situation in her life.  “There’s no one who at some point hasn’t had the feeling their life is on the rails and they can’t do anything about it.  “And I think that’s the real takeaway from ‘Descendants.’ No matter where you’re from, no matter what has happened, no matter what situation you’re in, no matter what people have told you that you can’t do, you can.”  Ortega says Cameron underscored that point herself in her approach to making the movie.  “Dove came in here without a lot of dance background,” he says. “But she was determined she was going to learn what we needed, and she kept pushing until she did. Zac Efron did that on ‘High School Musical.’ When you’ve got one kid who pushes like that, it makes everybody go harder.”  “I had never walked into something I felt so totally unprepared for,” says Cameron. “I had done a little dancing in a show choir in high school, but I'd never danced like this.  “And I love that situation. That’s how you learn. I absolutely wanted to raise my game.”  Toward that end, Ortega says everyone pitched in. “Kids like Sofia Carson and Cameron Boyce, who had more experience, helped the others,” he says. “My whole thing is that it has to be fun, and this was a blast.”  Having adult veterans also helped, Ortega and Cameron say.  “Kristin Chenoweth had been my personal idol since I was like 6 or 7,” says Cameron. “When I first met her on the set, I was totally star-struck.  “But she was so generous, professionally and personally. We got to be close friends — and not in a crazy-fan way.”  Cameron says she tries to learn from every role, and that includes “Liv & Maddie,” which she says also started as a leap into the unknown.  “When we started,” she says, “we didn’t even know if the whole thing thing would work.”  Then it became one of the network’s most popular shows, and Cameron says she hopes the third season, which they’re now filming, will segue into a fourth.  “‘Liv & Maddie’ has given me a lot of tips on how to do crazy stuff,” she says. “There’s not much I could imagine that we haven’t done on the show.”  Cameron also has a recording career queued up, so she stays busy — though she admits her secret isn’t necessarily the best one.  “I work all day and because I’m social, I always stay up and do things at night,” she says. “I’m running such a sleep deficit right now that I may never catch up.”  She might want to keep her calendar open, though, for more “Descendants.”  Disney loves franchises, and Ortega says that if things break right, this one could be prime fruit.  “There was a definite point in filming [the first one],” he says, “where I knew we’d accomplished what we wanted to accomplish. We were filming in a garden and I just thought, ‘Yeah.’  “When we wrapped filming, there were the usual tears, laughter, hugs and so on. And we all looked at each other and while no one said it, we were all thinking, we hope we do this again.”
'Descendants' brings together the children of some of Disney's most famous villains, and has them sing and dance, of course.