Hi!
If you want to see the Drawing Overrides Menu, you have to expand the "Object Display" Menu because Drawing Overrides is a child of Object Display.
But this tab wont help you achieve what you want, since drawing overrides are purely cosmetical.
To make your geometry unselectable you either set it to "Template" in the Object display Menu, but that will make your geo appear in wireframe mode.
So the most common way to do this is to create a layer with your geometry on it and set the Layer Display mode to "Reference".
I hope it helps!