I think Supergirl would come out on top. Supergirl is a superhero with amazing abilities. While ghost stories can be spooky, they often lack the kind of physical power that Supergirl has. She can use her flight to avoid any spectral attacks and her strength to fight back if needed.
She might face the challenge of intangibility. Ghosts can be intangible, making it hard for Supergirl to land a physical blow.
Supergirl could potentially win. She has the same powers as Superman under a yellow sun. Her heat vision can be extremely powerful. If she uses her speed and heat vision in a coordinated way, she could overpower Wonder Woman. Also, Supergirl might be more adaptable in different environments as she has had to face various threats on Earth and in space.
I think Naruto would be more likely to win. He has so much power at his disposal. He has the Nine - Tails' chakra and has mastered Sage Mode. Minato is strong, but Naruto has faced and defeated much stronger opponents than Minato ever did. Also, Naruto has the will of fire burning bright within him, which gives him an extra boost in tough situations.
One possibility could be a story where Supergirl, with her super strength and flight, teams up with Ghost Rider. They could be fighting a common enemy that is causing chaos in both their worlds. Maybe a powerful demon that has escaped from the underworld and is causing havoc on Earth, and Supergirl's powers combined with Ghost Rider's hellish abilities are needed to stop it.
Lex Luthor could be a great villain. He might be jealous of Supergirl's powers and see Flash as an obstacle in his plan to defeat her. He could use his scientific knowledge to create some sort of weapon that targets both speedsters and Kryptonians.
One inspiring Supergirl story is her fight against powerful villains to protect Metropolis. She uses her super strength, flight, and heat vision to keep the city safe. For example, when a group of alien invaders threatened the city, Supergirl was the first to stand up and fight them off, showing great courage.
Perhaps there is a prophecy in the fanfiction that only Supergirl and Ghost Rider together can fulfill. This prophecy could be related to saving the multiverse from a great evil. They would have to embark on a long and dangerous journey, facing many trials along the way. Their relationship would develop from reluctant allies to true friends, and maybe even more as they grow closer through shared experiences.
The Joker could be a really interesting villain in this fan fiction. He could somehow find his way to Metropolis and start causing chaos. His insanity and unpredictability would be a challenge for both Red Hood, who has a history with him, and Supergirl, who has never faced such a deranged foe. The Joker could also try to drive a wedge between them to make the situation more difficult.
I think the Ghost Stories would win. Ghosts are often depicted as having otherworldly powers that can't be easily countered. They can pass through walls, possess people, and cause chaos without being physically present. The Reckoners, on the other hand, are limited by the laws of the physical world. Even if they are smart and well - equipped, they may not be able to deal with the unpredictable and often illogical nature of the entities in Ghost Stories.
It depends on the situation. In a fight against a villain with super - strength and no ranged attacks, Supergirl might be more dominant with her own super - strength and flight. But if it's a villain who creates complex traps in a city environment, Spiderman's agility and web - slinging could make him more dominant.