The photograph doesn't simply show the EGS, but the TTK(EGS + built in battle simulater) which was used as a testbed for the NGP. How is that not a NGP prototype?
The EGS is not unrelated to the NGP, because it's appurtenant to the realization of the two-crewmen concept.
Do you have a source on the dimensions and road wheel size?
You apparently have little to no clue what you are talking about. Please try to check facts before spreading incorrect informations.