I have a feeling I've been down this path before, but here goes:
The Phillack Cemetery headstone lists show:
Isaac Newton d. May 20 1938, b. 1867, H/O Ellen Ellen Newton d. August 9 1957, b. 1919, W/O Isaac
I believe this is my Isaac, b 1867 Helston, painter, father Isaac Newton b. abt 1838 Penzance, painter; mother Ann Drewry b. 1838, North Deighton, Yorkshire. Isaac (1867) appears in 1881 census, Phillack, with his family, age 14. In 1891 census he appears as painter, age 24, living as lodger in St. Columb Minor.
Ann Newton does not appear with husband Isaac (1838) in 1891 census, Phillack, although she is listed on a monument d. April 30 1896, shared with Isaac (1838), d. 9 November 1903.
I'm looking for Ellen's maiden name and marriage to Isaac (1867). Given Isaac's advanced age at marriage, assuming Ellen was at least 15, was Isaac previously married? Did he have any children by any wife? He would have died only two or three years after marrying Ellen, if the dates from the monument are correct.
Looking forward to hearing from the usual sleuths!
A quick search of 1911 - I dont have any credits to verify - shows Isaac (1867)& Ellen(1870) both living in Redruth district (which I believe covers Phillack). It would be worth you checking to see if they had any children with them. and exactly where they were living.