In terms of game set up, yes you need the Division Commander (CinC).
Although unless something goes wrong his only role will be to pass orders to the BC.
You could effectively ignore his presence until such time as he has to "step down" to assume command of the Brigade in the event of the death of the BC or you want to detach a regiment for a specific task that does not comply with the overall Brigade Order.
That is a very small battle for General de Brigade.