When playing Icathian Rain, do you have to choose enemy targets in advance before the enemy plays a reaction?

Ruling: No, you do not choose targets when playing Icathian Rain. Icathian Rain does not itself target.

Sequence:

• Icathian Rain is played
• Enemy has opportunity to play reactions
• When Icathian Rain resolves, six instances of "deal 2" go on the chain
• Targets are assigned when those instances go on the chain