Well, I looked at that, and I didn’t see enough meta data to do that, and as far as I know, there is no public API to get citation variables from FamilySearch. I use RootsMagic to connect to that site, and I only get formatted citations from them. They must be using variables to create them, but they seem to be for internal use, just like the variables that our local archives make available to the Dutch portals. There is one portal that has these variables in their page source, but that’s about it.
This suggests that web scraping is the only thing that might work on the short term, or maybe just a sort of source import Gramplet, into which you can paste the relevant part of a page.
I’m just as lazy as you are, so I don’t like to use another program, even though I tested some.
P.S. When you install RootsMagic, you get a separate location database that lives outside your tree,
P.P.S.S. Can you give some examples of the sources that you use?