There are enough native North American superheroes from the Golden Age to make a team. In addition to the Bird Man, Buckskin, Mantoka, and Freezum, there's the Bronze Terror:
For the backstory on the character's creation, his first story, and a discussion of the racial imagery in the context of its time, see The World’s Scariest Lawyer – Daredevil Comics #2.
The Bronze Terror was probably inspired by the Black Terror. The Bronze Terror was created soon after the Black Terror and has the skull imagery that the Black Terror probably got from the Phantom. The "bronze" may be a reference to his race, but it was also used for black people--the Bronze Buckaroo was a black cowboy. If I revived the Bronze Terror, I would give him some degree of invulnerability to justify his name.
I haven't found any female Native American superheroes from the Golden Age, but if you came up with an excuse for time travel, fun could be had with Starlight the Warrior Maiden.
ETA: In my search for examples of Native American superheroes, I've been focusing on characters in the 20th century. But there were comics characters set in earlier times who could be called superheroes. See Five Native American Superheroes of the Old West - Mark Carlson-Ghost.
ETA: Johnny Fox doesn't have a costume or a secret identity, but his ability to turn invisible puts him in superhero territory:
Johnny Fox was a member of the Seminole tribe of Florida who became a US government investigator and took on missions around the world. His office was in New York. In addition to being an amazing fighter and athlete, Johnny's grandfather gave him invisibility pills, derived from an ancient Seminole secret, which allowed him to turn invisible for several minutes at a time. He also flew an amphibious craft called "The Flying Gator."