Dependent Children should not have their own Hubs. They are not Business Concepts and as such should not be a Business Key by themselves. They only make sense when associated with a Business concept.
One example is Line Items in a Order. The Line Item in Order by itself does not make sense. It needs to be associated with an Order. This makes a Line Item a Dependent Child i.e. it is not a Business Concept on its own.
One way to model the Dependent Child is to add them in the Link as following: