Everything here is from Missouri's Digital Heritage website -- specifically, the death certificate database.
Mary Minerva Curl d. 22 Nov 1936, and John Neal Curl d. 9 Jan 1937 in Penn Twp, Sullivan Co, Missouri. Other relatives of Isaac Stanforth who d. in Sullivan Co include Jasper N (21 May 1912)and his widow Mary D. Cox, dau of Peter P Cox and Elinor Beal, and Hannah Wright Stanforth, dau of Peter P Cox and Elinor Beall, widow of Amos F Stanforth.I found nothing on Amos.
Most everybody is buried at Mt. Olivet Cem, Prob in Pleasant Hill Twp, Sullivan Co.
There may well be more info that can be gleaned from the website.I pulled just a little to whet your appetite.Best of luck!