I think this would be REALLY FUN in a larger group including those who do art on a regular basis, and those who do not. We used cheap oil pastels, a set of pan watercolors with a water brush, some kids' markers, and ordinary pencils - nothing special, no professional "art supplies". You could also include glue-stick collage!
Can you think of other ways to use this process? Maybe life-size figures tacked to the studio wall, or imaginary plants (roots, stems, leaves, flowers) that could be assembled in different ways? Let me know your thoughts.