Thomas Callihan & Mary Broctor, PA

Have not folowed up on this old family info; help appreciated. I have Thomas (1757-1841) md to Mary Broctor "of English descent."Three oldest children supposed to have been born in Ireland. "They lived and died on Callihan Farm above Pleasantville at Alum Bank, PA. Two lonely graves are crudely but plainly marked on their 160 acre plantation." Supposed to be a land grant in Thomas name in Bedford County, PA.,supposedly given in recognition of his service in Revolution.
Children: (Boys last names are CALLIHAN unless noted and girls married names are in parenthesis.)
(1)John (Clarion Co.PA) md. Isabella Bowen(1785-1839)and kids were George, (1813-1897),Edward ,Robert, Thomas Blackburn (fought in Civil War,is buried at Arlington), and an unknown.
(2)Thomas Jr. md. ? McCreary and lived in Bethel Hollow (PA?). Kids: Mary(Snowden), Isabelle(Whitehill), Elizabeth(Bartlett), Jacob(Clarion Co.PA) and Amos(Johnstown, PA).(3)Robert Callihan(1792-1896) md. Margaret Rininger(1797-1845), lived on the old Tom Callihan Farm in Pleasantville, PA.Kids: Thomas, Catherine (Smith), Mary (Smith), Elizabeth(Harbaugh),Orpha(Arthus), Esther(Shaulus),Susan(Smith),George, Wm. M., Nancy(Wright), John (his name is on the monument at Little Round Top, Gettysburg)), Robert, Margaret(Valentine), & Sarah(unk).
(4)Jacob Callihan(1794-1879) md. Susan Mock(1800-1856) lived and raised family in Chambria Co., Johnstown and Richland Townships. "Buried alone in Grandview Cemetery, Johnstown, Sec #4, Lot #252." Kids: John, Elizabeth (died young), Sarah(Miller), Matilda(Layton), Mary Ann(Horner),Joseph (1828-1909), Mariah(Horner), David, Samuel (1835-1913), Beck(male), Susan(Boyer),and Jacob Ressler(1844-1915).
(5) William Callihan.Went west;nothing more known.
(6)Elizabeth Callihan(1784-1861) md. Wm. Oldham(1778-1854).Buried at old Crum Cemetery in Crum, PA.She was supposedly born in Ireland and was about 6 yrs. when family immigrated. He's buried in Sping Meadows (PA?). Kids (boys last name OLDHAM): Amanda, Mary(Jones), Alice(Wilson), Nathan, Hester (Hare), Elizabeth(Miller), William, Jaheau (male), and Jethreau(male).
I am advised by the Ulster Historial Foundtion (Ireland) that "a high proportion of the Irish who emigrated to America before the War of Independence were Presbyterians from the northern province of Ulster." Also: "...no official records of emigration from the British isles survive before the 1890's and no passenger lists whatever before 1800."
They enclosed a note on sources in the USA to check to try to establish a precise place of origin, recommending in particular naturalisation papers.