Your quest givers are Robots, notes found, computer terminals etc. All the humans that left the vault (which held 200 people but of which there are only 25 per server) are players. And it’s pick and choose, you can still micromanage and develop the settlement you want, turn a settlement over to the mod for a complete build, or add individual plot modules.ħ6 has npc’s but they aren’t human. They are impressive, and work well with some caveats, but basically that the latter can completely develop a settlement for you, or all you to add exterior and interior plots for the categories such as residential, agricultural, commercial, security with a minimum of fuss, in much more interesting configurations that you most likely would do building your own. They are tied together I believe by the same authort, the latter allows you to assign a citizen to build up a settlement for you.
I have discovered a couple of F4 mods, I’m excited about Sim Settlements and Rise of the Common Wealth. Some things have changed regarding what mods are available, and now they are managed, as compared to 2015-16, but not too bad figuring that out.