I can understand your point about Firmino.
I think he cannot replace Lucas Paquetá since one it is a midfielder and the other is a forward and Brazil needs to have a good midfielder. Otherwise, the ball will not reach the forwards.
I agree with you, Richarlison can be easily be replaced by Firmino, but the national coach thinks Richarlison fits better in the tactic.
Sorry about the confusion in position! I really wasn't looking at it. I was looking on the current performances of the players.
No problem ;)