For what it is worth, which may be very little. Oral history says that John Champion is the father of Margaret Henson's two children Rufus Henson and Samantha Henson Kirby. It is doubtful that this can ever be proven.
I gave up researching this line of my family in the 1990's because of the many dead ends.

I am a grandson of Alma Henson Dean, daughter of Rufus Henson and Mary Abernathy. She confided in me when she was alive that the family tried to hide the fact that both Samantha and Rufus were illegitimate. This is reflected in the death certificate of Rufus Henson where a different set of parents are listed for him. His son Howard Henson was the informant for the death cert. and listed the parents of Rufus Henson as Eford Henson and Julia McAbee Henson. There are no known records of these individuals.
Also the parents listed for the death cert. for Rufus do not match with the parents listed on Samantha’s death certificate. Again I believe this was all made up due to the stigma of the time.

My grandmother was only 10 years old when her father Rufus Henson died so she did not have many details, only that she had been told that John Champion and Margaret Henson were both from NC and both parents of Rufus and Samantha. She also supported that Margaret did marry John Smith later and had one son named John Smith Jr.

Unless new documents turn up, I suspect that the ancestors were able to keep their secrets and confuse the heck out of our generation.

I have never heard oral history that Margaret Henson was Native American, however I do recall my grandmother telling me of the physical features of her father and Aunt Samantha (who she knew well) and they were both described as having dark eyes, hair and skin tone. It would not surprise me if there is a Cherokee connection. I was never able to tie this Margaret Henson into the other Henson families of Rutherfordton, NC.

I have seen the 1900 census as well and agree that there is inaccurate information provided by the Henson's to the census taker. I also do not think that the Sara Henson listed is a child of Margaret. By the ages, it would mean that Margaret was about 8 years old when she gave birth to Sara.

I sincerely wish anyone all the best in researching this line. I would be rare to find many records on a landless, unmarried female such as Margaret during this time period. I would someday love to know the more myself.