I am wondering if your John and Margaret had a daughter Margaret Imrie who married a William MacKenzie in NYC in 1855. According to Margaret Imrie MacKenzie's death certificate she was born in 1833 in Scotland and came to NY in 1834. Unfortunately, NYC did not put parents names on the dc at that time. One of their daughters has the middle name of Drummond and one has the middle name of Imrie. Just curious.
Linda