I can not help with you questions, but I can provide input on Mary Chynoweth. She was born in 1855 to James Chynoweth and Mary (beskeen) Chynoweth. Their first daughter, Mary, died 29 Oct 1854. James died about the same time and the mother Mary about 2 years later. They had 6 children, Mary (28 June 1846), James Henry (25 July 1847), Elizabeth (14 Oct 1849), Eliza (1851), Catherine (13 Sep 1851) and then your Mary. I believe Elizabeth and Eliza died at an early age. Catherine was married 26 Nov 1871 in Gwennap. James Henry came to the United States and thus I exist since he was my great-great grandfather on my mothers side. James died in Phoenix Arizona on Oct 31, 1933. I have a letter from James Henry's daughter that says James Henry's grandfather was a John Chynoweth but I have not been able to confirm this.
After the childrens parents died, they lived with John Brown and Kesiah (Beskeen) Brown as stated in the reference letter above and confirmed by the 1861 census, folio 40, page 20, entry 107. I hope you find this of interest and use. Robert Malcolm