[+2]: You gain 2 life. Put two +1/+1 counters on up to one target creature. [–3]: Exile target creature. Its controller gains 2 life. [–10]: Creatures you control gain flying and double strike until end of turn.
2019-07-12
Ajani's last ability affects only creatures you control at the time it resolves. Creatures you begin to control later in the turn won't gain flying or double strike.
2019-07-12
If the target creature is an illegal target by the time Ajani's second ability tries to resolve, the ability doesn't resolve. No player will gain life.
2019-07-12
You may activate Ajani's first ability without choosing any target. If you do, you will gain 2 life. However, if you do choose a target and the target creature is an illegal target by the time the ability tries to resolve, the ability doesn't resolve. You won't gain 2 life.