Interpretation of Music Animatic

My next project for my Visual Narrative & Storyboarding class is about interpreting music in an animatic.  The song I'm using for my animatic is Saviour of the Dreaming Dead by Malcolm Brown.

And then here are some concepts for the characters:

The basic storyline is taken from the very beginning of my larger series, The Nays.  A group of kids find themselves in a mysterious World after heading through a portal. Basically I'm going to be focusing more on backgrounds in this animatic. Since I don't have all that much experience with backgrounds, this will be a more challenging take on the project. I've taken a bunch of reference pictures of the general idea of what I'm aiming for: