Anatomy and lighting critique for my illustration

[Elia_Vespera]

Hi everyone, I hope someone can help me a little, I've been stuck on this illustration for a while.
I'm having a lot of trouble managing the anatomy and the lighting

[malcom]

When it comes to the lightning on the characters, I think you can add some SSS(Subsurface scattering)

For the girl with the pink hair, I don't think we will see her right should from this angle like that with the pose she's in. Do you have a way to recreate the pose in real life?