LifelinkLifelink is a static ability.
Damage dealt by a source with lifelink causes that source’s controller, or its owner if it has no controller, to gain that much life (in addition to any other results that damage causes). See rule 120.3.
If an object is no longer in the zone it’s expected to be in as an effect causes it to deal damage, its last known information is used to determine whether it had lifelink.
The lifelink rules function no matter what zone an object with lifelink deals damage from.
If multiple sources with lifelink deal damage at the same time, they cause separate life gain events (see rules 119.9–10).
Multiple instances of lifelink on the same object are redundant. (CR 702.15)
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.
When Enduring Innocence
diesIs put into a graveyard from the battlefield. (CR 700.4), if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)