Back in October Christopher Loyd expressed his interest in appearing in a 4th Back to the Future. If they do bring back the classic, isn't Doc with a new lead and a fresh story would be pretty good. Maybe picking up from 2015 with an aged Doc and a kid going on a classic time traveling journey. Maybe the son of Mary McFly (Michael J. Fox). There is no word on an actual sequel, but here is an imagined Back to the Future Remake (Skinhead and 3-D aren't casted).
Elijah Kelley - Goldie Wilson
Kelley is really funny and I think that's needed for the future mayor of Hill Valley. Kelley showed off his comedic side with a small role in Red Tails and The Butler.
Spencer Boldman - Match
Boldman is currently on Disney's Lab Rats playing the role of an all brawn and no brain bionic hero. Match was as douchey as Biff and he didn't mind being bossed around. Boldman's acting ability and his look makes him a good fit. The role of Biff's lackey should be perfect for him.
Will Pourer - Biff
Maze Runner he was great as an authority figure and in We're the Millers he was funny. Stared in Son of Rambow as kid if you haven't seen any of his performances you're missing out. Dude can bring the funny and he has the intimidating size needed for Biff.
Stefanie Scott - Jennifer
At just 18 she's just really getting her feet wet. Scott has taken part in the Insidious franchise turning in a really good performance in 2015's release as Quinn. In a teen movie where she becomes the lead of a band is why I picked her. She was cute, charismatic, she did well with the emotional scenes and that was enough for me.
Bella Thorne - Lorraine McFly
Fan cast favorite and for good reason. She's, funny, sexy, geeky all in one. Duff showed she can play the mean girl while her roles on TVs Shake it Up showed her comedic side. As Lorraine she would have to be a little more like her Duff character but a lot more likeable. There is no doubt she would do the role that Lea Thompson played so well justice.
Nat Wolff - George McFly
At first glance you might not be sold on the future Death Note star, but the man can pull this role off. Wolff is a major talent with some pretty good range. His role Fault in Our Stars showed his ability to be charming and funny. Those are the qualities that George's character needs. Wolff would add depth to an already tight class.
Jim Carey – Emmett "Doc" Brown
Loyld could indeed reprise his role as Doc, but if I were going to get a guy to capture Doc it would be the great Jim Carey. This is the role for him, Bruce Almighty, Fireman Ed (throwback In Living Color), Liar Liar, The Mask and the list goes on and on. Carey would kill this role playing the flamboyant, loud, mad scientist.
Dylan O'Brien –Marty McFly
Rounding the best cast ever is one of the hottest up and coming actors right now. O'Brien has versatility oozing from his veins. The Teen Wolf and Maze Runner star would make Michael J. Fox proud. He's just right to play the cool kid Marty McFly.