I do find it confusing that you describe your model as an explanation of the OSI model and then go on to explain that it is different.
There are many layered models for traffic over different kinds of network and several in common use on the Internet. None of these uses the OSI model, and the most common (TCP/IP) breaks it quite significantly - almost as much as your Lego model does.
The OSI model is a theoretical stack of seven specific layers which may be used as a reference to compare and clarify differences in the other models.
Rather, I would see your discussion as a basic introduction to layered networking in general rather than specifically to the OSI model.
Also, the user data en bloc is not really a network layer. For example the OSI top layer stops at ensuring correct delivery and maybe reassembly to the right logical recipient, it has no concept of what James actually cut up. so really, you have produced a four-layer network model.
But I do like your approach.
"Klinger, do you know how many zoots were killed to make that one suit?" — BJ Hunnicutt, 4077 M*A*S*H