It is looking like Elizabeth Logan who married James Wilson was born Aug 17, 1873 in Montclair Township, Essex County, New Jersey to parents George Logan and Elizabeth Johnston. That could explain why John Caldwell Johnston died in Montclair in 1938.
On the 1880 census, in Westchester, New York, we have George Logan, age 29, wife Elizabeth 29,and daughter Elizabeth 6 (would later marry James Wilson) with sister-in-law Jeanette Johnston who is single, age 34, so age is not correct to be Janet Fish Johnston who was born abt 1865.