Hi I'm interested.
My portfolio: https://www.artstation.com/darkcan
Considering the complexity and amount of characters in the illustration I'd said that 400$ would be a good. As for time I can tell you a minimum of 3 days and a maximun of 6. You'll have full right for the illustrations I would ask for credits of course and if you would allow me to publish the illustration in my social media.
Here some examples of my work:
