???
There's only 4 people in the picture. If you mean the 6 chairs, I don't think that means anything. You would think they would have shown 6 people in the Nintendo Direct if it was possible.
But they only NEEDED 4 people... Oh, as hard as I may hope, I don't think that my dreams of more people in multiplayer will happen.
True, they only needed 4 people. But you have to admit that 6 players would be a pretty important feature to show off right?
I don't think the chair in front of Brewster activated the music cut-scene. I think the two extra chairs positioned in front of K.K. Slider could be for animals to view the performance.