Odds are we’ll know who this new New Mutant is long before the film comes out.
Now the reasons for the length of the delay are a little more clear; the reshoots that New Mutants is about to undergo are really extensive.
The latter two would both require a lot of additional special effects, but Cypher could be added on the cheap.
The film already featured New Mutants cast members Magik (Anya Taylor-Joy), Cannonball (Charlie Heaton), Wolfsbane (Maisie Williams), Sunspot (Henry Zaga), and Mirage (Blu Hunt), along with Dr. Cecilia Reyes (Alice Braga), a character who was briefly a member of the Marvel Comics X-Men.