Raid Bombardment's ability won't do anything when a creature you control with power 2 or less attacks a battle.

The power of the attacking creature is checked only when the ability triggers. Once it triggers, Raid Bombardment will deal 1 damage to the appropriate player or planeswalker even if the creature's power changes before the ability resolves.

If you attack with multiple creatures with power 2 or less, Raid Bombardment's ability triggers for each of them separately.

A creature with 0 power can attack, as long as it doesn't also have defender.

If the attacking creature leaves the battlefield before Raid Bombardment's triggered ability resolves, Raid Bombardment deals 1 damage to the player or planeswalker that creature was attacking before it left the battlefield.