Many of the earlier musicals had a 'star' of the song, a lead in the scene. In this, everyone was equal. There were times when only two were active, yet the transitions were so fast and the group came back together quickly it really appeared to be a well choregraphed team.
The same goes for the costumes, they all coordinated and looked like a group. When looking at them all four on set, they all seemed to blend together. Your eye was not drawn to any one thing.
The transitions were great - everything timed so well. It was fun to watch and re-watch!