Hi everyone,
I was just windering if there is a Mod to disable Sims changing into special clothing for interactions, like the kids who play racing on the sofa, using the mechanical bull etc.

I am not sure, but maybe you can try it by using Dresser and MC for Blacklisting the items a sim wears at that moment
Dresser-FAQ#How-do-I-tell-the-mod-which ... for-random

use the first method, you can delete the items from your blacklist if it does not work.

I don't know of a way to prevent the special outfits from spawning, but I do know how to delete them if you need new ones generated. Clicking on the Sim and using DebugEnabler's "Fix Invisible Sims" resets ALL of the outfits including the Special category ones, allowing a new outfit to generate next time the game requires one.