Only the controller of “Spring of Rebirth” gains Life Points by its effect. If you control “Spring of Rebirth”, you gain Life Points even when a monster is returned to your opponent’s hand.
You gain 500 Life Points each time a monster or monsters on the field are returned to their owner’s hand. So if “Penguin Soldier” returns two monsters at once, you only gain 500 Life Points.
Spirit Monsters are sent to the owner’s hand one at a time during the End Phase. So if you have 4 face-up Spirit Monsters during the End Phase, you will gain 500 Life Points for each, totaling 2000 Life Points.
Multiple “Spring of Rebirth” cards are cumulative.