I have turned the story progression off in my game, as well as aging, and age the sims manually with the master controller (just change their age in CAS), because I want to control each single aspect of the game. I do not have any story progression mods installed.

However, I've noticed that sims still do certain things by themselves, even with story progression off. They go to community lots, which is good. But they also get jobs autonomously, and I see new families moving into the houses in town. So, I don't actually know what to expect from them now.

What can sims do autonomously with the story progression off?

You'll be able to turn more of that off with Nraas Story Progression actually, including turning off immigration.

They shouldn't be moving or getting jobs if story progression is off. I play my game with story progression off, because I like to switch between all the families in a cycle and my sims won't do much of anything. Actually, they don't do much besides standing around in front of their respective houses and most of the time, I'll return to a family to find them failing at school or work. But if I go to a community lot, there tend to be other sims there.

Anyway, it sounds to me like you still have story progression turned on.

I have Nraas Story Progression, cause I wanted to populate a town myself, I turned off immigration and I even made all the empty residential lots 'no visitors allowed' community lots, but the stupid pudding faced bastards keep moving in - Where? I do not know... *insert Twilight Zone theme here*

I'mma have to look at every setting I have on mods and on the actual game itself, 'cause it's driving me mad.

You will get service sims 'moving in', though not to houses of course. I'm interested: If you shift-click the mailbox and choose 'Make me know everyone', then look at the town, do you see random sims living in houses? If so then immigration isn't turned off.

@OP: Sims will get jobs if your sim gets a job, to fill in the Boss and Co-Workers slots.

You most likely have a Stylist Station or Cash Register in town, correct ?

The sims you are seeing are role immigration. Install Register, and they will stop appearing.

Cheers, will do!

The sims aren't actually "getting jobs", they're being forcibly dragooned into them to fill nebulous "coworker" requirements, and there is no good way to disable this or prevent it from stealing YOUR sims, unless you are running AwesomeMod. Don't think anyone else has an anti-dragooning mod, and I'm not sure it is possible to stop this without a core.

A non-core approach is to simply give every sim in town a job, since the system only dragoons unemployed sims.

StoryProgression also replaces retirement with a "Retired" career, which stops elder recruitment.

Cheers.

Ha! I've installed the register mod and created appropriate looking sims to man the posts! I will soon be able to run all the homeless out of town! ahahaha!

That doesn't entirely stop the problem, or cure some of the other messes the system creates, so it's still more of a bandaid-on-chest-wound sort of deal. The system is really a horrible mess. The game will actually still dragoon sims even if they do have jobs: It will randomly promote them in the process, then possibly drag their workplace across town if there's more than one.