The cloud remains invisible to me as well. I'm testing it in Maya 2018 with Arnold and I am unable to assign a volumetric shader to it.
In the cloud's attributes panel only one channel, "Easy cloud 01," is listed under Grids and Velocity Grids. Other VDB files include several channels here with names like "density," "heat," etc.
Maya throws six errors when I try to assign the shader, two each for "Easy," "cloud," and "01." So I wonder if this might just be a naming issue since "Easy cloud 01" includes spaces.
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Size of the calibration chart on import is 100 x 100 meters, so that's off by a factor of 100. The FBX camera imports to the correction location.