Yes and before that Update the setting only worked in worlds with settlements off, which is only the case for migrated worlds from 9.7 or dedicated worlds that were made that way, but not newly created singleplayer worlds.
Absolutely, you can configure everything about the settlements system in Settlements.eco
It is easiest to edit it via the server ui when you start the dedicated server executable, as that will show descriptions for the settings, but the requirements are set here:
"MinCitizensToFoundSettlement": [
3,
12,
30
],
Number of citizens in order Town, Country, Federation.