Since I was not able to find any into on the forum, I’m posting here. I’ve not been able to duplicate a symbol as a new symbol, not an instance. That way when I modify the contents of the new version it doesn’t affect the original. Maybe I’m not finding this.
Second, when I convert an object on the stage to a symbol, it make the symbol as large as the stage, not the actual symbol size, which is smaller than the stage.
I was able to go into the symbol and modify the contents to fit the object inside, but this took many steps and time. An option to only make the symbol as large as the contents would be a real time saver.
You can export the symbol under a different name and then import it as new symbol.
To duplicate a symbol, not an instance, you can follow @mackavi answer: right-click the symbol in Resources pane, select export, then import it as a new one.
For the second question, the symbol must have the same size as the stage to keep its responsive layout design. It may cause inconvenience in case users want to create non-responsive symbols. We’ll try to improve it in future releases.
Not a problem. I’ve been moving objects to the top left corner, creating a symbol, resizing to fix the contents, and then moving it back. Either way is not too bad.