Yes the gravestone says William John died 1875 but I have his death certificate and it says Apr 27, 1876 in Kinloss. Wrong date on gravestone. I also have the death certificate of Agnes his wife and it says Dec 27, 1864. They did have a son Alexander born Aug 5, 1832 unverified who died Apr 7, 1907 unverified in Saltford.Dates are correct for James F. son of Alexander and I have 1876-1881 for Mary L., daughter of Alexander.
I could use the death of daughter William John's daughter Mary Mattison who possibly died Jan 1880 in Willowdale, Dickinson, Kansas to see if it mentions her brother William who I am pretty sure died between 1875 and 1880 in Weston, Dunn Co., Wisconsin but I can't prove that, either by death certificate or burial records or community history books or the Wisconsin Archives or Wisconsin court records. You see, her brother William had a son Alexander in 1876 who is with his step grandparents in 1880 (Mattias Henderson) and the only reason I can think of is that William and his second wife Mary Anne Olsen had both died between 1876 and 1880, while William could have died before Alexander's birth in Apr 1876. I looked for guardianship records to prove that but if the records existed, they don't now. William's first son William from William's first marriage to Margaret Henderson is also with Mattias in 1880 and I never find that son William again (age 10 in 1880)
The other sibling who died closest to William's possible death is James C. Johnston who died Oct 7, 1902 in Kincardine. I have his death certificate but not an obit.
Peggy