Once the owner dies the Illagers in the Woodland mansion will become neutral and you can tame them with a totem of undying and now they can help you fight mobs also Iron Golems will not attack the neutral illagers since the owner is dead The Vindicator for example it's a lot more stronger and doubles its speed and strength you can also trade with it sometimes but not all the time if you hit it it will hit you one time but it still Tamed