Thanks for the response! Using CSV with the Import Text gramplet was my first impulse too. (Although the other information you mention about the weirdness is also interesting/concerning. And I did/do not recall the OpenRefine data-washer example. Time for some research and experiments.)
The Places CSV support even includes the Date header. And it looks like you should be able to stack the Enclosed_by entries by using the Square brackets for the ID too.
Place
place - a reference to this place
title - title of place
name - name of place
type - type of place (eg, City, County, State, etc.)
latitude - latitude of place
longitude - longitude of place
code - postal code, etc.
enclosed_by - the reference to another place > that encloses this one
date - date that the enclosed_by place was in effect
But the tough part seems to be the “avoiding rework” side of the “cloning” idea. It is and obvious timesaver to compose the Place creation CSV data to do all 16 townships at one time. But the efficency in singleton cloning requires being able copy the existing hierarchy.
The Place view mode export does not include a Enclosing Place column. Even if it did, it wouldn’t handle more than 1 entry nor their couplings with date ranges. And exporting a selected Place to XML is not a feature
(Even when using the Isotammi addon XML exporter that supports a full Place tree export. That option is not available in the built-in XML exporter.)
I suspect that it will require writing a SuperTool script to do the cloning. sigh.
The script could be similar to the examples by @PLegoux to list the Enclosing places to a table. So you could use the Copy button in its GUI to clipboard the data to paste into the Import Text gramplet.
Or script could do the whole cloning. Hmmm. Might even be able to spawn a New Place editor dialog with the Place Type and Enclosing Place data pre-filled.