>So, NewObject can be used in either case. AddObject is only used with a container. CreateObject would be used in a non-visual, non-container class. I can use either NewObject or CreateObject in my case then. Why even have CreateObject if NewObject can do the same thing?

The NewObject() allows to specify class library as second parameter. The CreateObject() requires SET CLASSLIB beforehand. You could find that from the help though.