The proposal is iteresting.
But I can't imagine why, in the secondary layer(s), the element han to be not-editable. If it can be seen (and this is our goal) let it be editable...
The only difference, with "home" layer and "secondary" layer(s) would be in deleting the layer (in the first case the element is also deleted from the secondary layers) and locking layer. If the Home layer is locked, the element is locked in all layers.
To assign a single element to more tha one layer for visibility will require an interface, maybe a pop-up window (like the show on story [...]), with a checkbox for every Layer.