You choose the opponents for each effect as the spell resolves.

In some unusual cases, the Spirit tokens will have a toughness of 0 or less as they enter the battlefield, perhaps because an opponent controls an enchantment that gives your creatures -1/-1. Because state-based actions aren't performed in the middle of a spell's resolution, you'll gain 2 life for each of those Spirit tokens. After Benevolent Offering has finished resolving, the Spirit tokens will die and subsequently cease to exist.

You may choose the same opponent for each of the effects, or you may choose different opponents. None of the affected players are targets of the spell.