The most best book on Capt. Thomas Coram is "Thomas Coram, Gent., 1668 - 1751", by Gillian Wagner, published by Boydell Press in 2004. It incorporates the information in the books you mentioned, and adds a lot more. The book is in print; I bought it from Amazon last year. His father was probably a clerk in the Custom's Office at Lyme Regis, Dorset. His younger brother, William, died in infancy. Thomas married, but had no children. Thus, there are no descendants. The connection to Ottery St. Mary is a common belief, but the exact family lineage from known families in Ottery St. Mary has not been established.