After you take the picture for back, I like your idea of combining his work and yours. As the mother of 2 grown sons and 3 stepsons, all with strong personalities and most with children, the combination of his childhood effort and yours into a useful and enjoyable art keepsake will be appreciated I think. However, to be sure, I'd sketch it out and talk with him about what you're thinking of doing, he may have further input. I also wouldn't use cartoonish, babyish animals. I'd use realistic ones, that way it can be incorporated into a growing child's room, not just a nursery. JMO I look forward to pics of your project!