Question 1: Say a player has a sword that enables him to add 1d8 damage as a free action whenever he hits an enemy. Can he choose to activate it upon a critical strike for an automatic 8 damage, or does he need to say that he wants to activate the weapon BEFORE making an attack roll? Or does damage from free activates simply not figure into automatic max damage from a crit?

Question 2: Say a player is about to make a coup de grace. Does anything prevent him from using several free action damage add ons from various sources (powers, magic items, etc) for a big damage boost?