I love games like this. I frequently picture actors when scripting my scenes, I find it helps with establishing characteristics and quirks on the page. Although not all of these actors have the exact characteristics of the character they've been assigned, hair colour isn't something I consider when it's an easy aesthetic to fix. Also, monstrous characters such as Toad and Blue Devil have been cast with their human actors in mind for personality interpretations.
X-Men: Mutant Underground
Thor Knai as Warren Worthington III (Archangel)
Stanislav Ianevski as Piotr Rasputin (Colossus)
Lily James as Alison Blaire (Dazzler)
Lily Collins as Kitty Pryde (Shadowcat)
Brittany Snow as Charity Cornell (Dreamer)
Freddie Stroma as Jedidiah Anders (Freakshow)
Gemma Whelan as Sarah Rushman (Marrow)
Eddie Redmayne as Mortimer Toynbee (Toad)
Chaske Spencer as James Proudstar (Warpath)
Ashley Rickards as Morgana Delcourt (Wicked)
New Mutants
Ngô Thanh Vân as Xi'an Coy Manh (Karma)
Clémence Poésy as Illyana Rasputina (Magik)
Julia Jones as Danielle Moonstar (Mirage)
Alicia Vikander as Amara Aquilla (Magma)
Gael Garcia Bernal as Julio Richter (Rictor)
Donald Glover as Roberto da Costa (Sunspot)
Halston Sage as Collins Macarty (Bloom)
Martin Sensmeier as Harrison Hodges (Totem)
Justice League Dark
Rosalyn Sanchez as Alba Garcia (Black Orchid)
Boyd Holbrook as Daniel Cassidy (Blue Devil)
Mena Massoud as Khalid Nassour (Doctor Fate)
Emma Watson as June Moone (Enchantress)
Matthew Goode as Jason Blood (Etrigan the Demon)
Gary Oldman as Erik (Mister E)
Zoey Deutch as Eve Eden (Nightshade)
Saoirse Ronan as Siobhan MacDougal (Silver Banshee)
Odette Annable as Zatanna Zatara