This question has been answered by iusemodx. See the first response.
To duplicate a page:
goto the page you want to duplicate: click edit, once in the page => press the "duplicate" button (top right)
Once pressed, follow the instructions and that's it
You may have to rename the alias if you are using FURLs, if you want the page to keep the same alias name, you will have to set the config to allow duplicate aliases
A kind of workaround:
If all of the pages are in a folder - duplicate the folder and it will duplicate all of its contents as well