So I've been working on this for about 2 hours. and I was satisfied mostly with the cave part, though I think perhaps it could use some more detail. Then I got to the people, and tried doing quick silhouettes. I think they look pretty bad and I need suggestions on how to do them. I hope to work on this tomorrow and perhaps finish it.
I'm probably the last person here who should be commenting on your "people", having no drawing skills at all. But what says they have to be "people"? Seems to me you're creating a fantasy world here and the beings that inhabit it are up to you to define. My suggestion is to just go with your flow and let it happen.
I like it! It's eery and hopeful at the same time