Literally the only problem that needs solving is the fact that I can't get Duchess to survive. And I don't see any way to make that happen without more blessing level on her. So, the next best alternative is to try to get someone else to take the hit, and ensure they survive - that's how I did it in all the previous rotations, with Razel being the person surviving.
You could try what I did ... I just had enough support to keep rezzing and healing over and over, I think you have all the champs I used. Sometimes my dutchess was targeted and lived and sometimes she died. I originally wasted a ton of silver making artak low hp high def but he still never took the hit constantly and he still would just die even at 5 star awakened.