[Answered ]-Traverse foreign key and pull remote model data into Django admin

You should be able to access any field in the first model as: firstmodel__value12

For the list view for the SecondModel:

list_display = ('firstmodel__value12',)

For the edit view you can use formfield_overrides. To make it non-editable you specify a read-only widget, e.g. like this one or provide your own.