Interesting. Another Tappan-Homes descendant was the wife of American naturalist / entomologist / horticulturist Theodore Luqueer Mead. Her own father was the well known lepidopterist William Henry Edwards.

Jan mentioned possibly finding more on the Downie, Raa, and Baxter ancestry of Agnes Baxter, wife of Mr. John Heart, minister. Another possibly fruitful avenue of research might be to seek the ancestry of David Heart, the father of Mr. John. I suspect he is the "David Heart" listed in 1597 among the servants of Mr. William Hairt/ Heart of Leviland. https://babel.hathitrust.org/cgi/pt?id=msu.31293024812277;view=1up;seq=429 Mr. William was also called "of Preston" or "Prestoun": "Maister William Hairt of Prestoun" was one of the Justice-deputes in Scotland, and presided under that designation at [the plotter] Sprot's [1608] trial. He appears to have been knighted very soon after the trial, and the reason can scarcely be doubted. This respectable functionary drew up an official account of the culprit's examinations, confessions, and execution, which was prefaced by a long and abject sermon in favour of the king, by Dr George Abbot, dean of Winchester, soon afterwards made Primate of England. This _ex parte_ account of the matter, so important for his majesty, the courtly dean immediately published ... https://books.google.com/books?id=ckgMAQAAMAAJ&pg=PA283&dq=%22william+hairt%22+depute&hl=en&sa=X&ved=0ahUKEwiy4OCN2rjUAhVESiYKHbmcCp4Q6AEIUjAI#v=onepage&q=%22william%20hairt%22%20depute&f=false David Heart, the servant in 1597, may have been a nephew or other agnate kinsman of Sir William Heart/ Hairt. A few years later, around 1600, David apparently transferred into the service of the Elphinstone family.