Is there a special virtue for one who prays directly behind the imam? And is it permissible for someone who comes late to sit in the advanced rows instead of completing the first row? And what is the ruling on that action?

The worshiper should be keen not to harm his Muslim brother, to overlook some actions, and to advise the wrongdoer gently. As for being close to the Imam in prayer and standing in the first row, it has great virtue, as he becomes a role model for others, and is able to correct the Imam's recitation or act as his successor when needed. This indicates initiative in doing good and desiring it, while delay indicates laziness.