As I said, it depends on which of the two approaches you want to pursue. If you have a friend who is good at Python, that’s great. He might want to do a GitHub search for Panchanga to find Python code that either does the calculations or connects to the API.
So if you add your Panchanga dates as event properties (approach 2), this can be done via the Python standard library, using the csv module that reads and writes the csv file format as exported and imported by AT3.
In case you want to specify the entire calendar with Panchanga (approach 1), and there are lots of eras to be created, things are a bit more complicated. Then there’s no way around manipulating an AT file, and that requires a bit of investigative spirit. Your friend might find some inspiration in my code here. and here. There’s also a comprehensive discussion on the aeon file format here in the forum.
In any case, it can’t hurt to first create a calendar for a manageable period of time by hand to see if the result meets your needs. Only then is it worth considering automatically generating the calendar for the entire period.
Good luck,
Peter