Okay maybe this could be solved similar to https://gerrit.wikimedia.org/r/#/c/201446/1 . The script just defines a class or so which takes some keyword arguments. Each Wiki has then a MediaWiki:FOO.js JSON content (where FOO could be defined by the script or maybe pywikibot-<scriptname>). It then loads the JSON content and calls whatever is there to initialize the settings. So in the case of my patch the page would contain then on the English Wikipedia:

{
    "name": "Orphan",
    "aliases": ["wi"],
    "parameters": "date={{subst:CURRENTMONTHNAME}} {{subst:CURRENTYEAR}}"
}

And it would do then something like that in the script:

settings_page = 'pywikibot-lonelypages'
pywikibot.bot.load_settings(settings_page, OrphanTemplate)

And then in the library we have a function which does some magic:

def load_settings(page_title, callback, site=None):
    site = site or pywikibot.Site()
    page = pywikibot.Page(site, page_title + '.js', 12)
    if page.exists():
        return callback(**json.loads(page.get()))
    else:
        return False

We could do something similar also to implement some family configuration variables (like where the categories/interwiki links go) like suggested in T89451: Reducing complexity of the Family class.

Change 201446 had a related patch set uploaded (by XZise):
[FEAT] Load the settings from wiki

https://gerrit.wikimedia.org/r/201446