Matthew has mentioned the first English speaking Transfiguration parish here:
One of the converts he mentioned was a gentleman named Reginald Wright Kauffman. Kauffman lived from 1877-1957 and was a noted author. He also served as a newspaper editor for a time. He was raised Episcopalian and apparently considered Mormonism for a time. He and his wife Ruth authored a book on it in 1912. You may still purchase a reprint from the University of Illinois Press. Despite this, he became Orthodox at the Transfiguration parish in New York in 1920. Here is a newspaper description of that event:
To the best of my knowledge, he remained Orthodox, but I am not sure of that. Fr. Daniel H.B. Montgomery mentioned Kauffman as a “pioneering convert” in “Your Orthodox Mission to America” Word Magazine (1957): 207-8, 212. This need not mean Kauffman remained Orthodox and if anyone has any information on Kauffman that relates to his Orthodoxy, we welcome feedback.