Does EVS use standard kriging or does it consider how mobile contaminants are, etc?

No kriging algorithms specifically consider the mobility (viscosity) of the analytes (contaminants).  Actually, in most cases the the conductivity of the geologic materials, including their anisotropy can have a more profound effect than the typical variations in viscosity of most hydrocarbons (except perhaps tar).  However, EVS does have the ability to set fully anisotropic variograms which directly affect the kriging and therefore have a profound impact on the interpolation (and extrapolation) of contaminant samples.  This is not done “for you automatically” since it would require far more information and insights than are typically (ever) measured on any site.
There is an Advanced Training Video specifically on this topic: Advanced Variography in krig_3d which teaches users all of the techniques and nuances required to utilize fully anisotropic variography to optimize your kriging results.