I love this idea! I can't wait to try it with my son when he gets a couple months older. By the way, what you have there is a glockenspiel. A xylophone is made with wooden bars, not metal as you have. It's a common mistake!
I'm aware of what the xylo- in xylophone means. But words mean what we use them to mean, not what pedants insist upon, and in vernacular, you're wrong, not him: the meaning of xylophone includes metallic instruments in the same style. In musicology, sure, these distinctions are useful there. But what I want to stress is that you are wrong in this context. Not technically correct: wrong. The only mistake was you choos…
Your approach leads to calling them all sticks.