I looked through your files and all seems to be correct except that you've put your diffuse map wrong, should be in color instead of diffuse, but this shouldn't affect your exporter as you can override this later anyway.
Do you have the Stellaris project selected in the exporter when clicking "add shader attr."?
Do you have your settings file in a folder called "settings" under PdxExporter?
Do you have the Stellaris project selected in the exporter when clicking "add shader attr."?
Do you have your settings file in a folder called "settings" under PdxExporter?