I was able to answer a few of my own questions. William Henry came to New York on the Henry Ellis (1863). Joseph came to Boston on the Susan Pardew (1864). William Sr. went to England with George (son) before coming to America. In England, he met and (it appears) had a relationship with Sarah Ann Gunner (daughter of Harriet Francom), who gave birth to Jane Francom on 25 Dec 1867. William, Sarah and Jane all came to New York on the Cella (1869). When he left Utah in 1870, Sarah went on with her life and married James Reese. Amy died in 1876. It appears William (living in England) married Martha Moore in 1878. I'm trying to find out what happened to Jane Francom and who she married.

The sources (with more info) are posted on my webpage: http://www.francomfamily.com .