Multiple aliases per node (and active trail)
A simple solution is to create Content Type, say 'delegated', with a single node reference field. Then, configure the reference field to point nodes of the content you want to be duplicated. Configure this field to show the referenced node as full node view (or whatever View mode you prefer).

This way:


You can create independent pages with their own title, breadcrumb, alias, metadata, etc, but same content (if they reference the same node).
Editors are able to update/create those 'delegated' node easily (they are just a node).
As reference field can be limited by a View, you can narrow the contents available to be referenced in a powerful way.


As all are nodes, you can even create admin views to see with contents are related, or any other node available operation.

The main drawback is if you have configurations in referenced nodes that you want to be in the referencer node (say metatags). This could be solved using a custom module (updating referencer metatags when referenced node is updated) or manual copy-paste (ugly).