Theory: Sims you created showing up as hired npcs. ( Mixologist, Babysitter, Maid...ect.)
I usually play several households at once and recently i noticed that sometimes your sims can show up as service npcs such as Mixologists (even non hired ones), Maids, Handymen and even caterers. At f...
The family trees were intact upon inspection as well, so these are definitely original sims and not just copies. If this is how the game chooses service npcs, it's pretty rad.