Regarding second part of the question.
If You do changes to Your local scene, original references are not changed. They are stored in material files, like this:
%localappdata%\Itoo Software\Forest Pack Pro\lib\Presets\Layered_Lawns\matlibs
If You modified these files, then modifications would be inherited in all presets going forward. (though they will be overwritten again with our library version on next Update Manager update)
Hope that is what You asked for. If not, please specify question a bit more and we will try to help You.