Lizzy Caplan as Tamara Winters/Domino
Domino is a skilled, mutant, mercenary, who possesses, the ability to manipulate probability in her favor, giving the effect of incredible luck. After joining with the X-Men, she is currently a member of Cable's new X-Force team.
Reason for Casting: Caplan has been the underscore in some big films including 127 Hours and Cloverfield and has proven her charisma and charm in films like Mean Girls and The Interview. With some good direction I feel she could definitely be the leading lady of the X-Force, an object of Deadpool's affection, and a gun-toting baddie.
Kim Kold as Nathan Summers/Cable
Cable is the time-traveling son of Cyclops. He was infected with the deadly techno-organic virus at a young age, which he kept at bay using his advanced psionic powers. He also raised the mutant messiah, Hope Summers.
Reason for Casting: Kim Kold definitely looks the part and has shown he can deliver lines and also be the muscle in films like Fast and Furious 6. Kold also gave a wonderful performance in the film about a bodybuilder which currently holds a 93% on Rotten Tomatoes called Teddy Bear.
Malese Jow as Betsy Braddock/Psylocke
Brit beauty Psylocke is a mutant with vast telepathic and telekinetic powers that she can focus into deadly weapons. She is a stealthy martial artist, a former fashion model and longtime X-Man. She is currently a member of both Cable's X-Force and Storm's X-Men team.
Reason for Casting: Appearing in The Social Network and the hit TV show The Flash, Jow has no shortage of appearing in big roles. Her acting chops are something to be improved upon but for a character that isn't necessarily an A-Lister among the likes of Cyclops and Wolverine, I feel Singer and whatever director may helm the franchise in the future can elevate her name and polish her acting.
Anna Kendrick as Anna Marie/Rogue
Once a member of the Brotherhood of Evil Mutants, Rogue has since become a veteran member of the X-Men. After many years, she has finally gained conscious control of her power to absorb the thoughts, abilities and memories of others through physical contact.
Reason for Casting: Anna Kendrick and Rogue share little more than a first name but despite this I feel Kendrick could be a very convincing Rogue with her roles in films like 50/50, Pitch Perfect, and Up in the Air she could bring justice and portray a shy, introvert feel that Anna Paquin brought yet give us the fierceness that comic book fans have been wanting from the Singer X-Men Universe.
Bo Burnham as Bob, Agent of HYDRA
Kidnapped (or liberated) from his post at a HYDRA base by the mercenary Deadpool, Bob is a surprisingly normal guy. Deadpool's feelings for Bob range from friendship to considering him a pet.
Reason for Casting: A very talented comedian and TV star known for his stand-up specials and time on Parks and Recreation. Ideally appearing in a Deadpool movie, Bo and Ryan Reynolds could have some hilarious back and forths.
Jamie Chung as Jubilee
Jubilee, once a teenage mutant, became a member of the X-Men who could release colorful explosive plasmoids and detonate matter at a sub-atomic level.
Reason for Casting: Chung's likeness was already used for the Jubilee concept art for Days of Future Past which leads me to believe they already talked to Chung for appearing as Jubilee in the film before her character was ultimately cut. This is why I think Chung who is already a talented actress could portray a great Jubilee.
Hunter Parrish as Samuel Guthrie/Cannonball
Cannonball is a mutant with the ability to propel himself through the air like a human rocket. Over the years, Sam has grown from a New Mutant, to the leader of the original X-Force, to a full-fledged X-Man. He currently teaches at the Jean Grey School and is an Avenger.
Reason for Casting: Appearing in the recent Oscar contender flick Still Alice, Parrish has a very promising career in film. Bearing resemblance to the character and also having a very small filmography is Parrish were to appear in a CBM, I doubt he'd be anything but stellar.
Dane DeHaan as Bobby Drake/Iceman
The youngest member of the original X-Men. Bobby is an Omega-level mutant, although it took some help from Emma Frost to realize this. Bobby's control of ice is vast; he can create shields, clones, spikes, slides and also freeze others. He currently teaches at the Jean Grey School for Higher Learning.
Reason for Casting: DeHaan isn't going anywhere soon in CBM's considering Marvel's recent purchase and planned revamp of the Amazing Spiderman franchise. That being said I think he could portray a very conflicted Iceman having trouble coping with his mutant powers before Emma Frost helps him.
Nick Robinson as Jamie Madrox/Multiple Man
Jamie Madrox, also known as Multiple Man, is a mutant with the ability to create duplicates of himself through physical contact. These "dupes" can later be reabsorbed, along with all of their memories and experiences. Madrox runs X-Factor Investigations, a mutant detective agency.
Reason for Casting: Robinson is a promising young actor with leading man potential that's easy to see. Him playing a young Madrox could definitely boost his appeal as a comedic actor and also enhance his dramatic work. In the X-Men Evolution cartoon series Madrox was clumsy and a "junior" X-Man and I could see Robinson playing that interpretation of the character very well before eventually growing into the more well-known comic book version of the mutant.
Hannah Murray as Kitty Pryde/Shadowcat
Kitty Pryde, also known as Shadowcat, is a mutant gifted with the ability to become intangible and phase her body through solid material. A talented prodigy, she became the "poster child" of the X-Men. Since "Battle of the Atom", Kitty has left Wolverine to join Cyclops and now mentors the time-displaced original X-Men.
Reason for Casting: Hannah's work on Game of Thrones has really impressed me and the few movies she's been in were only so-so but it's not her fault they were bad. Hell, she was just an extra in Dark Shadows but everyone pretty much knows GOT doesn't cast bad actors/actresses. Upon seeing her performances in a series of binge watches I think she would be the perfect Kitty Pryde.
Rebecca Hall as Emma Frost/The White Queen
The former White Queen of the Hellfire Club, Emma Frost is a powerful mutant telepath who can transform herself into organic diamond. She has become an eminent member among the X-Men. A gifted teacher, Emma is renowned for her beauty, wit, and revealing attire.
Reason for Casting: DO-OVER! January Jones as Emma in First Class was not bringing justice to a great character. That being said, I've concocted a short headcanon as to how Emma's character can return even though it's confirmed she was killed in DOFP. You know how in The Last Stand, Charles transfers his consciousness to another body before death? He had to learn that from somewhere right? Say Emma did the same thing considering her and Charles share the mutant power of telepathy. Hall is a great actress that's appeared in films such as The Town, Frost/Nixon, and Red Riding: 1974. She was reduced to an extra in Iron Man 3 so I doubt even the most diehard fanboy can call her on being in two universes. Dye her hair blonde and watch magic happen.
AnnaSophia Robb as Alison Blaire/Dazzler/Songbird
A mutant with the ability to transduce sound into light, which often forces her into reluctant superheroism. She is also a very gifted singer and performer, hence her reservations in donning her uniform.
Reason for Casting: Dazzler could use an awesome movie treatment as I always thought with the right direction she could be very interesting and Marvel's certainly trying with her recent recreation of the character. I prefer her to be portrayed as a soldier of Charles's ideology but still being reluctant to battle. Robb has been in a string of good films including The Way Way Back and Bridge to Teribithia so her acting is certainly good enough to bring this character to the big screen.
Willa Holland as Paige Guthrie/Husk
Husk is a mutant with the ability to husk her skin to expose a new type and layer of skin underneath. Originally a member of Generation X, Paige graduated into the X-Men and is currently working at the Jean Grey Institute of Higher Learning as a Junior Faculty member.
Reason for Casting: Holland has impressed critics and fans alike on shows such as Arrow and her performances in films such as A Summer in Genoa. Holland has a young innocence as seen that can definitely have a viewer believe she is the younger sister of Cannonball yet also a valiant leader to be.
Mae Whitman as Laura Kinney/X-23
Laura is the product of a different section of Weapon X. She was cloned from Wolverine's damaged DNA - from the salvaged part of his X chromosome - and born to Sarah Kinney, her mother and the scientist who made her birth possible. Since she could walk, she was trained to be the perfect replication and killer of Wolverine. Under Wolverine and Gambit's guidance, she has since 'found herself'.
Reason for Casting: Whitman is known for her action packed role in the cult classic film Scott Pilgrim vs. The World as Roxy Ritcher. Since then she has appeared in other films with critical acclaim such as Perks of Being a Wallflower and Tinker Bell. With her diverse filmography Whitman could be the perfect foil/ally to Wolverine.
Thomas Sangster as Jean-Paul Beaubier/Northstar
Twin brother Of Aurora, Northstar is the haughty mutant speedster affiliated with the X-men, though he was originally a member of Alpha Flight. He is most famous for being the first openly gay superhero.
Reason for Casting: Appearing in Nowhere Boy and having a role in Game of Thrones, Sangster could definitely deliver the emotion and bring Northstar and his personality to life on the big screen.
Garrett Hedlund as Douglas Ramsey/Cypher
With the cerebral ability to understand all languages, Cypher was considered to be one of the weakest New Mutants. He was best friends with Warlock, but was killed while defending Wolfsbane in battle. He was forcibly resurrected during Necrosha, and soon returned to the X-Men as a powerful strategist.
Reason for Casting: Cypher would be an important member of the newest X-Men team as he is one of the rare mutants that discovered their powers during adulthood and seeks Xavier's Institute to help control his powers. Hedlund has been in films including Inside Llewyn Davis and Friday Night Lights.
Hana Mae Lee as Xi'an Coy Manh/Karma
Karma is a mutant with the ability to mentally possess other beings. A founding member of the New Mutants, she is one of the few confirmed and openly lesbian characters. She lost a leg and now has a cybernetic one in its place.
Reason for Casting: I haven't kept up much on comics so I was not aware Karma had a cybernetic leg. How cool would that look in a movie? But back on topic Karma is another young mutant that resides in the X-Mansion with the power to control others. She's seen as a potential successor to Xavier's dream along with a young Jean Grey.
Brie Larson as Hope Summers
The first mutant born after M-Day, Hope Summers is believed to either be the mutant messiah or the harbinger of death for humanity. She is an Omega-level power mimic, and possesses a connection to the Phoenix Force.
Reason for Casting: Appearing in films such as Short Term 12 and The Spectacular Now, Larson has proved her great acting abilities over and over again. That being said, if we ever get a flash forward into the future Larson could definitely portray the Mutant Messiah and adoptive child of Cable, having raised her since birth.
Fátima Ptacek as Megan Gwynn/Pixie
Pixie is a fairy-winged mutant who can cause those exposed to her dust to experience hallucinations. Magik forged a fragment of her soul into a dagger which can disrupt magic and mystical beings. Pixie is a teleporter by means of a teleportation spell. She is a member of the X-men.
Reason for Casting: Ptacek is a talented young actress known for being the voice of Dora and starring in the Award-winning short film Curfew which was turned into a feature length film titled Before I Disappear.
Imogen Poots as Lorna Dane/Polaris
The mutant mistress of magnetism, Polaris is also the daughter of Magneto. After a long sojourn in space she rejoined the ranks of X-Factor, fought alongside the X-Men against the Avengers, and now leads Serval Industries' All New X-Factor.
Reason for Casting: Imogen is another actress I seriously hope gets cast in a CBM soon having quite an impressive resume with films like Me & Orson Wells, Jane Eyre and Solitary Man. Poots is also in the right age bracket to bring the Polaris/Havok relationship to life on the big screen with Lucas Till while also being young enough to be the daughter of Michael Fassbender's Magneto.