Joseph Porter Falloon went to U.S. in March 1912 (see below) but was back in Belfast by the end of August when he registered the birth of his son James Houston Falloon (registered child's death a few weeks later).
2 Mar.1912 “Campania” arrived N.Y. from Liverpool: Joseph Falloon, 25, foreman, Belfast, wife Mrs. Fallon 7 Parker’s Place Legoniel, going to friend Mr. W. Acheson 15 Van Patten St. Auburn NY, 5’4” fair complexion fair hair blue eyes.
James Houston Falloon (26 Aug.1912 Ballysillan-8 Sept.1912).
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1912/01484/1604237.pdf (informant- Joseph Porter Falloon, father, preparing master, 7 Parker Place)
https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1912/01484/1604237a.pdf (informant- Joseph Porter Falloon, father, preparing master, 7 Parker Place Ballysillan).
https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1912/05360/4494208.pdf (congenital debility, informant- Joseph P. Falloon, father, 7 Parker’s Pl., present at death).
His wife Georgina died 1957 in Belfast. James & 2 other children died young, not sure what happened to daughter Elizabeth.
Next possible sighting is of a Joseph Porter at 10 Charlotte St., Birmingham (1922)- does this address fit with any of the birth certificates for children of Gertrude Harris?
1927-1939 Joseph Porter Falloon is at 66 Repton Rd., Birmingham (this is his address from Probate record).