Rather than converting the geostatistical layer to a raster and extracting the points, you should just use the "GA Layer to Points" geoprocessing tool. It will bypass the creation of the raster, and merging all of the outputs will be easy.
Also, you might want to consider using Empirical Bayesian Kriging (EBK) instead of Ordinary Kriging. The results are generally more accurate, and EBK is implemented as a geoprocessing tool, so it is much simpler to automate.