Emily was born Harriet Emily Hoffman in Baltimore. Her father Samuel was a wealthy merchant, he died in 1852. Emily's sister Sophie married Louis McLane. The McLanes were living in San Fransisco in the late 1850s. "Emmie" went to stay with them to help her sister care for their samall children. Louis introduce "Jimmie" to Emily in 1859. Then Lieutenant McPherson was the chief engineer at Alcatraz and had an office in Montgomery Block near to McLane's own office.
If you send me an email with your questions, I will be happy to answer as best I can. The Hoffman family and the McLane family were both members of Baltimore's elite families. Another reason why Emily's mother did not want the couple to marry. James was the son of a blacksmith, and was a "Union" officer. He was not from the same class as Emily. Not the "Hoffman" marrying type. Emily's sister Sophie married the son of an abassador and former secretary of state. Louis McLane was a wealthy man in his own right having made a fortune in the gold and silver rushes in Nevada and california. He started the Bank of Nevada and the Wells Fargo Bank. So, the son of a blacksmith with no "history" and ceratinly no money was not a fit suitor for Emily.