It's great to hear your family search was successful albeit over a long time.
I can find only eight registrations for the children of John Gordon and Ann JORDAN.
A summary of dates to show that Charles Alexander GORDON ‘fits’ between Jessie and John/Robert John.
Anneb. 25.11.1876d.22.2.1877 Elizabeth CHURCHb. 26.12.1877 d. 18.9.1918 Robert Johnb. 4.2.1880 d. 21.1.1881 Isabella RUSSELLb. 5.11.1881 Jessie Pearl ROBERTSONb. 27.8.1885 Johnb. 15 1.1891 aka Robert John James William b. 4.12.1892 d. 6.7.1893 Anneb. 17.6.1895 d. 14.3.1898
Definitely four surviving children in 1924 including Charles Alexander born c1888 m.4.9.1929aged 41yFather John GORDON d. 28.8.1961 aged 73y