Duriel just get more damage reduction on your minions and they will be fine. basically the tankier you are the tankier they are, so just get more survivability.
Harbinger is horrible, all I can suggest is putting your golem on the cage and make sure you don’t click on the cage or your golem will just run in circles around it. You need to place it a little away from the cage, but not on the side where the portals are.
Then you just wait the 30+ seconds for your golem to kill the cage if you are a hybrid minion build without a strong golem active.
Im using bone golem so all he does is taunt on active 