North Georgia Cherokee lineage

My daughters maternal grandmother, before their deaths,stated that they were descended from the Cherokee. I have been using Ancestry.com to try and trace their heritage, and there is one location in their tree that I cannot find information. That is my daughters’, grandmother’s great-grandmother Lucy Jane Lee (b.1838, d.1880), who married John P. Huff. All I can find about her is her father’s name is Hyatt Lee (b. 1762, d.????) and her mother’s first name was Mary (cannot find a last name)(b.1802).

I am figuring that because of marriage to a European Descent, Mary and John were not forced on the Trail. But I am looking for any information that would conclude that in fact that this Mary was a Cherokee, and I want to know what clan she was.

The Lineage I have from my daughters (as suspected to Cherokee) up are as follows:
Mother – Anna Lavender (1968 – 2013)
Grandmother – Sonia (Huff) Lavender (1940-2008)
G’ Grandfather – Clarence Foster Huff (1899-1969)
G2′ Grandfather – Joel Billups Huff (1880-1920)
G3′ Grandmother – Lucy Jane Lee (1837-1880)
G4′ Grandmother – Mary ????? (1802 – ????)
If anyone can help me with this it would be greatly appreciated.