Black Bolt(Blackagar Boltagon) - Tom Hardy
A great actor with great physique and proven fighting skills,he will bring so many thing to the Inhuman king,maybe Vin Diesel is a decent choice but he will be 51 in 2018.
Medusa - Isla Fisher
Fisher is a little short for Medusa but has the charm,the beauty and the acting abilities for the character.Plus it's hard to find a 5'11'' actress with Fisher's carrier and acting.
Karnak -
Peter Mensah
Great fighter,stunning physique,proven in action and i think he would be great as Karnak.
Gorgon - Manu Bennett
I don't know what to say about that choice,when i look and compare these the following two pics i see Gorgon in both.
Triton - Daniel Sharman
Not very famous,a young and fresh actor with the proper physique to play Triton.
Crystal(Crystalia Amaquelin) - Saoirse Ronan
To be honest,i saw Ronan as Crystal in a ton of other fancasts and i think she's perfect.
Lockjaw - Mark Hamill CGI
It would be fan to fuse the two big Disney's properties(Marvel/Star Wars) and Hamill has a puppy like face.
Quicksilver(Pietro Maximoff) - Aaron Taylor-Johnson
With his sister,and maybe other Inhumans , he will try to find his similars.
Scarlet Witch(Wanda Maximoff) - Elizabeth Olsen
Like Quicksilver she will take the train to the inhumany.
Quake(Daisy Johnson) - Chloe Bennet
With her in the movie it's a good way to crossover the films and the TV.
Thane(Thanos' son) - Eddie Redmayne
Thane,son of Thanos,could play a great role in the end of phase 3 and in other future phases.I consider him as the reason for Thanos helping Maximus to destroy the Inhumans.
Redmayne is a great actor,a rising star in Hollywood and also is similar with Thane's human form.
Inferno(Dante Petruz) - Joaquin Furriel
Decent actor for a small role,he also can play Inferno in Agents of Shield.
Maximus the Mad(Lord Maximus) - Colin Farrell
Very good actor,great carrier and has the looks and the craziness to play Maximus.
Corvus Glaive - Christoph Waltz
Now that The Other is dead Thanos need new servants.
Waltz is an incredible actor,he would be stunning as a villain in MCU.
Proxima Midnight - Irina Shayk
Corvus' wife also an ally of Thanos.
Shayk is tall,majestic,in Proxima's 'size' and it will be interesting to see her in a big brand name like Marvel's.
Thanos - Josh Brolin
He will try to find and maybe kill his son and will make Maximus his puppet to achieve it.
Matriarch Oola(Oola Udonta) - Eliza Dushku
A royal Inhuman from Yondu's(Guardians of the Galaxy) race.She could alert Black Bolt for Thanos.
Dusku is a fan favorite actor and has worked with Whedon in the past.
Ronan the Accuser - Lee Pace
I think he can appear in a flashback to show us the Inhumans origin/creation.
Director Phillip Coulson - Clark Gregg
Like Quake it will be interesting to see him.
Nova(Richard Rider) - Zac Efron
In a post credit scene,making an alliance with Black Bolt,Thane,Star-Lord and Captain Marvel something like the annihilators to stop Thanos.
A growing star,with a big fanbase.He's coming in the MCU and i think he's Nova.
Captain Marvel(Carol Danvers) - Emily Blunt
End credits,like Nova.
Blunt 's a better actor and more famous than Katee Sackhoff.
Star-Lord(Peter Quill) - Chris Pratt
Who?