Vexing Radgull is a little niche, but I actually think in many ways its a stronger Thrummingbird for proliferate decks
As for protection, we can protect K'rrik, Son of Yawgmoth from some forms of removal with cards like Undying Evil, though it doesn't protect us from exile effects like Swords to Plowshares unless we also have a sec outlet like Viscera Seer to make sure K'rrik is going into the graveyard
The problem is the number of other six-drops that seem good in the deck, like Nissas Renewal, Greenwarder of Murasa, and Conduit of Ruin
Deck List Alesha, Who Smiles at Death x3 Generator Servant x3 Master of Cruelties x4 Wildfire Eternal x2 **Lightning Greaves x2 Break Through the Line x3 Liliana, the Last Hope x4 Fiery Temper x4 Kolaghan's Command x4 Collective Brutality x2 Dreadbore x3 Thoughtseize x4 Blood Crypt x4 Canyon Slough x4 Field of Ruin x3 Foreboding Ruins x4 Mountain x4 Swamp x3 Sideboard: **Damnation x3 Captain's Claws x3 **Gut Shot x4 **Lightning Bolt x2 **Whispersilk Cloak x3 **Cards Not Pioneer Legal
As a card with the Bodyguard keyword, Minnie Mouse may enter play exerted, and must be the target of your opponents Challenge (or another character you have exerted with the Bodyguard keyword!)
You get far more style points, however, by Transmuting it for a nine-mana spell like Kozilek, the Broken Reality or Portal to Phyrexia