If a nontoken permanent that's a copy of Enduring Vitality dies while it's a creature, it will return to the battlefield as an enchantment when its last ability resolves. It won't have any card types other than enchantment.

A token that's a copy of Enduring Vitality won't return to the battlefield when its last ability resolves.

Elk and Glimmer are both creature types. Enduring Vitality won't have those creature types when its last ability returns it to the battlefield because it won't be a creature.