The Surname I Was Given

Witherell is the surname I was given at birth. By my dad Harold he was known as Pete. I have never met anther person with Surname of Witherell. I”m only child and my father was married before to a lady name Louise. They ended up getting divorce.
My dad had no sibling by his father. He had sibling by his mom (Elsie Miller) who remarried a man of Rolph Wells.
My great grandparents Duane and Dora Stansell had two boys. Maurice and Clarence. Well Clarence is only one who got married and had one off spring. Maurice died do to the 1906 Earthquake in San Francisco.
Duane was the son of Gilman and Mary-Ann Simpson Witherell. They had 5 children. The oldest being George who married Suzie Church I know they move to Los Angles area and I know of one son Burt or Bart.
There next child was Henry A who married Susan Barnes/Bunner from New York they had one son Harley. Henry died in Tennessee during the civil war do to disease
The third child was a girl and died when she was 12.
The fourth child a male also died when he was young.
The baby of the Gilman and Mary Ann was Duane.
I know Gilman had a brother name Theodore.
I should tell the place of resident Gilman, his brother and son came from Concord New Hampshire area and went to Michigan in cass county. The rest was born in cass county michigan. But I don't know if George descent are left. If Harley had any descent or not. Theodore Gilman brother does he have any living descent.