AFAIK, the plist file contains the general Lightroom settings, or have you found a .plist file with the name of the catalog?
I would think that using an empty catalog as 'template' should be the easiest method by far.
There is only one Preferences file for LR. So when you create a new catalog is should carry over whatever your preferences are set to. At least that is how it has worked on my system right now.
That is other than the Lightroom Sync settings as IIRC they are stored in another folder called Sync Data and in another folder called Sync.lrdata.
The reason that is separate is because you can only sync to the web/mobile system from one catalog at a time.
There is a preference file that contains the general Lightroom preferences, but of course each catalog also has its own catalog settings. That is what the OP is looking for. AFAIK, these setting are stored inside the catalog file, however. Not in a separate plist file.
There is a Preferences dialog, and file, and a Catalog Settings dialog. The OP said Preferences. They are the same for every catalog created as there is only one LR Preferences file. Change the preferences in one catalog and that get changed in another catalog you open, whether old or new catalog.
Catalog Settings are store with each catalog and there is a Default template used when creating a new catalog. I don't know anyway of modifying the Default Catalog Settings. So if it is the Catalog Settings dialog he want to be the same I don't think that is going to happen.
Yes, the OP said 'Preferences', but from the context of his question (and the title of this thread) I assume he means the catalog settings.
He can achieve what he wants by making a 'catalog template'. Create a new catalog, change the settings the way you want, and use a copy of this (empty) catalog each time you want to start again with a new catalog.