Well lets be clear what cloning means. When you clone an object you create a brand new object with the same pv's, behaviors, attributes, etc. This also increases the games total object count.
Copying, and pasting on the other hand just creates another instance of that object, and does not add to your total number of objects, even if its in another layout.
So cloning, and copying are not the same thing in the editor. However cloning a layout (right click the layout in the project tab) creates a brand new layout, with no new objects, only the existing ones from the copied layout.
You should also be aware that objects can have more than one behavior, and most behaviors can be enabled/ disabled at the start of a layout.