How do reactions and actions interact with Falling Star, specifically when can someone react and when do you choose targets?

Ruling: You choose all targets for Falling Star's reflexive triggers at the same time, before either trigger resolves. Players can react at three different points during Falling Star's resolution.

Sequence:

• Players can react before Falling Star resolves
• After Falling Star resolves, the reflexive triggers go on the chain and you choose all targets at once
• Players can react before either reflexive trigger has resolved
• The first trigger resolves and deals 3 damage (if able)
• Players can react before the second reflexive trigger has resolved
• The second trigger resolves and deals 3 damage

Nuances:

• All targets are chosen at the same time, before either reflexive trigger has resolved