Hello Margaret, it is a pleasure to meet you online. I am descended from Henry's brother John (who was my grandfather), so we can't be too far removed. In the 1925 Compromise which finally settled the distribution of Samuel Oliver Pierce's estate (40 years after his death!), Henry is listed with his daughters Marjorie and Beatrice.
I was fascinated to hear that your branch also has a copy of the
Journal of S. Pierce's Tour to the United States of 1853. It must have made quite an impression on the family for different members to handwrite a copy for themselves. I assume Samuel Oliver Pierce wondered if he was related to President Pierce, but any relationship would have been remote, since the President's ancestors had been living in New England for over 200 years. However, if you compare surviving pictures of the two gentlemen, the possibility of a common ancestor cannot be ruled out:
President Franklin Pierce:

Samuel Oliver Pierce:

Incidentally, I do not think Samuel Oliver Pierce was ever a coach master. A subscribers' list of about 1840 describes him as a conch master, which was a popular item of jewelry in Victorian times. Most likely he made them as well as sold them in the Soho jewelry store. At that time he was living in Maida Hill (Paddington), and we have a
Child's Book of Games that his son Septimus won as a school prize while they were living in that house in the 1840s. My guess is that he retired from the jewelry business around 1850, bought Ryde House in Twickenham, and had the time and money to live comfortably and do some travelling. We have another journal that he wrote of a trip to Paris in the 1860s.