I had to use the GM toolkit a couple of years ago. At the time GM offered a half day training class. It covered how to use the toolkit as well as what GM will and will not accept. It was a great help.
UG will not export the drawing views from the drawing application. You would have export the drawing sheet as a DWG file and then import it into a modeling view, then export that as a CGM. An alternative that I like to use is a software called SnagIt it is easy to use, gives you a quality image...
I believe that the suggestion of grouping the features is the way to go in this case. However there is a toggle button that you can check either on or off that will hide all of the features of the group in the model navigator. If it is checked you will not see the features or be able to edit...
I can't remember if it was V17 or V18 but UG used to have have an issue with importing and exporting STEP files. They did however patch it. My suggestion would be to make sure that you are using the latest QRM for the version you are using. You can download the QRM from...