[Brightcolours]

Are yo able to ascertain if, after distortion correction, the corrected image from the lens has the FOV of a rectilinear 16mm lens, or is it less?  

That is always the case.. Under-corrected lenses show a wider FOV than well corrected lenses (same with the 14mm from Samyang, for instance). So in that sense, you do not lose anything when you correct in post processing. But you do lose in image resolution.