Characters for Environmental Non-Profit

I'm working on a mobile game for an environmental non-profit where my fiancé works. I'm looking to create 5 characters: Barry the Rain Barrel, Rutheford Pervious III (pervious pavement), Sister Cistern (basically a larger rain barrel), Terry the Tree, and the Rain garden. The game is a top down sim city style game. its a game for kids, and they can place rain barrels, trees, etc. throughout the game city and learn about the environmental benefits of doing so. Ideally I would like to have several pieces of artwork for each character. I would use them as graphics that pop up in the game( for example the levels designed to teach kids about rain barrels would have Barry on the screen and I would add a text box next to him explaining how rain barrels work, etc.) I would also use the artwork as coloring book pages that can be unlocked by beating levels in the game. Ideally I the images would be line art so that they could be used as images for children to could color in. I have attached some sketches that I had come up with before I realized that I was definitely not talented enough to do it on my own! I'm not sure exactly how this works, so please feel free to email me with any questions.