Heroic abilities will trigger only once per spell, even if that spell targets the creature with the heroic ability multiple times.

Heroic abilities will resolve before the spell that caused them to trigger.

If multiple +1/+1 counters are placed on Bloodcrazed Hoplite simultaneously, it last ability will trigger once for each of those counters.

Bloodcrazed Hoplite's last ability will trigger whenever any +1/+1 counter is placed on it, not just ones due to its heroic ability.

Heroic abilities won't trigger when a copy of a spell is created on the stack or when a spell's targets are changed to include a creature with a heroic ability.

If Bloodcrazed Hoplite enters the battlefield with +1/+1 counters on it, its last ability will trigger once for each of those counters.