UPDATE: I just tested the deck again, and WON AGAIN. Albeit it was on my second try this time; my dragonhawk got obliterated the first time.
There is definitely some kinda bug in play here that prevents minions from attacking/removing my dragonhawk for some reason. I literally just won with a 14/1 dragonhawk with divine shield and 3 enemy minions, yet they all attacked my face rather than the minion for unknown reasons.
I'm guessing there's some kinda bug where the AI chooses not to target a high attack/Divine Shield/Deathrattle minion for some reason, meaning you can exploit this bug and just go face the entire time (outside of Val'kyr Shadowguard and taunts).
I'm going to continue testing this, but if you run into this as well, let me know!
2
It worked really well got it on the 8th try (never lucky with Obliterate or Blizzard ) but eventually got there.
I changed Enter the Coliseum to Mossy Horror witch was clutch turn 8