You are correct. All of the Five Tribes were involved in the peculiar institution in some manner. Probably the Seminoles the least and the Cherokees the most. The Chickasaws were reputed to be the most skilled slave-catchers to be hired anywhere.

I’ve been involved in the fight with modern Cherokee racists over tribal enrollment of the freedmen.

If you want to get a closer picture, look up John Horse (a black Seminole chief) and Shoe Boots (a generally well-liked Cherokee whose serial affairs with black women made him a pain in the ass to tribal government.