The yellow Dark Samus represents Lance, the yellow Twin Striker who serves as the yellow half of Bayonette.
The blue Samus minion represents Spear, the blue Twin Striker who serves as the blue half of Bayonette.
The stage represents the Desert Palace, a desert-themed Holosseum in Custom Robo Arena which features a desert setting and a ruined castle.
The music track represents the musical theme of Chōsōjū Mecha MG, which features customizable battling robots similar to the Custom Robo series.
The stamina battle condition references the battle gameplay of the Custom Robo series where each player must deplete the opponent's robot's HP to 0.
Dark Samus and Samus' favored Missile references Bayonette's Twin Bombs attack, which allows them to fire explosive missiles.
Other trivia:
This spirit's Attack type and Steel Driver Equipped ability further reference Bayonette's Twin Bombs attack, which allows them to fire explosive missiles.