Originally Posted by horatio
They look similar to the stuff Spock and Pike wore so they are probably dress uniforms and will most likely only appear for a few minutes on screen. I doubt that they discard the three-colour standard uniforms if just for compositional reasons. Hard to imagine this shot with everybody wearing Mao grey.
Maybe the uniforms had something to do with an official occasion, as the case of a funeral scene? That would tie in with the house scene.