I know they stack damage wise, but how exactly? Can the bonus damage from Rapidfire crit if you have Statikk? Is Statikk Shiv's damage applied to towers like Rapidfire? Does the Rapidfire bonus damage count toward the multitarget of the Statikk?
They simply do the higher damage of the two possibilities. Given that Shiv has higher damage at all levels, that is always Shiv against non-towers. Since Shiv does 0 damage to towers, it is Rapidfire's bonus damage against those. And since the multitarget damage is coming from Statikk, Rapidfire does not interact with that.
