I agree with the third statement because I think that I need to prepare extra exercises for the children who finish early, it is not good if they have nothing to do. Well, sometimes there are a few children who are quiet and prefer drawing but most of them start playing or talking to their friends, even if those friends haven`t finished the activity yet.
However, I think that the extra activities wouldn't be so long because it would be just while the other children finish the first activity. The kind of exercises depends on the age, topic and time. Nowadays we have several sources where we can find lots of activities so, there is no problem to adapt or modify any of this.