Massacre Girl is basically a board wipe, and if youre into killing your own Creatures anyway, they might just be the best Commander for you
Ray Easygoing Firefly is a powerful late game card Ray has been one of my favorite five-cost questers in the game since it came out in Rise of the Floodborn, and I would actually recommend including four copies of him in your deck if you can (I would switch out the two Don Karnages for two Rays as I dont really know what Dons achieving in this deck that Ray cant also do)
We don't care about getting it cheaper, it's good at nine mana
Treasure Cruise A match made in heaven with Arclight Phoenix in Pioneer, and a house in Vintage, Treasure Cruise sees exactly zero play in Modern or Legacy but that's because it had to be banned, which is a testament to the power of Ancestral Recalls little delve cousin
When this happens, its usually a card thats hard to interact with without a sideboard, and that leads to a higher win rate in BO1 than in Best-of-Three (BO3)