I don't know if you have any spare space on the foam board, but a small square that would help make the side parts are vertical, but would also fit between the motor and side part would be helpful.
Super cool! But you are 100% getting a C&D from Nintendo. They are an EXTREMELY litigious company when it comes to defending their copyright. There is no question what those silhouettes are, and they are not significantly changed to make them ambiguous to Nintendo's likeness copyright.
