Still, you can't say there were no Cherokee in western Tennessee. There were. Not whole tribes, but as the British Army came into any territory, it hired Native people as laborers, servants. Guides, translators, hostelers, laundresses, cooks, and whores. And, as I've said before, men want women and when their own kind isn't readily available, they take what is, often for long term relationships. So, whichever William this is, he very probably did, as legend says, have a Cherokee wife/concubine/mistress/housekeeper mother of some of his children.