Long ago we visited my husband's Great-Uncle in Coral Gables, FL. He gave a condensed version of his family, during which he talked briefly about his father and grandfather - unfortunately he only used those terms, never their given names. I didn't ask, as I feared that he no longer remembered details. But perhaps this may help you with locations for research, if you were not already aware of these bits of information.
According to Col. "Gibby" Gibson, Retired, his Grandfather left Edinburgh, Scotland for Belfast or Londonderry. There he married an Irish girl, evidently a protestant, and immigrated to New Haven, CT. His Father (Robert J. Gibson) grew up and became an Army Doctor, married Ella Banks of New Haven, CT and fathered 1 daughter and 6 sons.