Adding to this universe (which I dub Earth 35 BCE after the Olmec and Maya's earliest appearance).
Speaking of Olmec, Black Adam (and to an extent Shazam) are that. Billy Batson would be of Purepecha origin while Wizard Shazam and the power are of Olmec.
Green Arrow: I wanted to expand past the well-known tribes/peoples and decided to go with the Omagua for Green Arrow. Like a lot of the peoples of the Amazon area, The Omagua are masterful archers.
Black Canary: One of my favorite interpretations of the character is the first Canary of Arrowverse, an outsider who fits right in. So, for Dinah, I chose Sami. Being a group from Europe, they could easily aid in the outsider aspect.
Red Tornado: Okay, I am gonna be honest, I am a sucker for Red Tornado. Massive fan. However, finding a good fit for them is gonna be hard. I decided to go with Puebloan for the fact of "Red Clay Hard Building."
Cyborg: I wanted to choose a group from Africa for Cyborg, not only to give Cyborg his rightfully origin but also shine a light on Indigenous Africans. For him, I chose Ogiek, a group found in Kenya.
Zatanna/Zatara: Ainu. I kinda forgot my reasoning....