My opponent plays Ajani Vegeant, and decides to -2: 3 Damage my Goblin Guide. I respond by casting Burst Lightning at my opponent, redirect to Ajani. Does my opponent remove 2 counters from Ajani for his ability and it's on the stack, then removes the remaining counter from my Burst Lightning damage and therefore dies before Ajani's ability resolves?
Or does he not remove the counters until the ability resolves, so my Burst Lightning resolves, removing 2 counters, and Ajani's ability never triggers because he doesn't have enough counters on it?
Additionally, if the first one is what happens, if a player casts Jace Balaren, uses his -1 ability to draw 1 card, I Burst Lightning in response, does that mean Jace dies, and also does not get to draw a card, since Jace is in the GY before it resolves?
Or does he not remove the counters until the ability resolves, so my Burst Lightning resolves, removing 2 counters, and Ajani's ability never triggers because he doesn't have enough counters on it?
Additionally, if the first one is what happens, if a player casts Jace Balaren, uses his -1 ability to draw 1 card, I Burst Lightning in response, does that mean Jace dies, and also does not get to draw a card, since Jace is in the GY before it resolves?