This person is a possibility for James:
Massachusetts, Births, 1841-1915
Citing this Record "Massachusetts, Births, 1841-1915," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/FXKZ-GYZ
James Lynch Male
Titles and Terms:
Birth 09 Feb 1915 Northampton, Massachusetts
Registration Date: 1915
Registration Place: Northampton, MA (p. 334 n. 48)
Recorded Date: Feb. 16th
Father William E Lynch
Father's Titles and Terms: Teamster
Father'sBirthplace : Granville
Mother Mary Mcgrath Birthplace Ireland
Residence of Parents: 89 South, W., F.
US Census, 1920 Northampton City Part Of 3d, Hampshire, MA
Citing this Record "United States Census, 1920," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MXBN-9D2
SELF William Lynch M 40y MA
WIFE Mary J Lynch F 40y IRE
DAU Catherine Lynch F 15y MA
SON William Lynch M 13y MA
SON James Lynch M 4y10m MA