Find the Greenbrier, not the place, but the woman. She was a daughter of Chief Cornstalk. Much older than her sister Rachel. Once you find Greenbrier and Reuben Kinnison, you find Rachel again. Greenbrier names Rachel Whitt as her sister. Look for them with William Parrish and his wife Elizabeth Kinnison. Elizabeth was daughter to Greenbrier and Reuben.
I have seen your web page. You have researched well, but are missing some information. You have a number of Hezekiah Whitts listed, one is in question. You have the one who was a son of Elinipsico. Raised to manhood by Thomas Mastin. Check your research and all your sources, you have already found what you need, it was in front of you overlooked.
:) Red Wolf
You asked in email who the brothers and sisters of Rachel were? Look on the internet, they are all listed. Have you not seen their names? Greenbrier is the eldest of the Cornsttalk children of the great Chief. He had many children with three women according to documented history. They may be more. A Chief could have had children with many women and it was not frowned upon by the tribe. It was considered normal to the people of the past. Now a days, it is common for Mormons to do this in secret, but it is not accepted by current law in any sort. Even Indians no longer practice this as a cultural way. It is now something only of the past.