Try to find a copy of "Pedigrees of Thomas, Chew, and Lawrance, A West River Regester, and Genealogical Notes", by Rev. Lawrence Buckley Thomas published in 1883. I have a copy that is in a very guarded condition, and cannot be copied. It does have a section on Hannah and Larkin Chew and their son John and Margaret; and John's son Robert and Robert's son Joseph, etc. It does go on for pages... There is very little about Ann and William Johnston and their issues. The only statement about their son James, is that he married Mary Ware. If you cannot find a copy of the book and are interested I will email you directly (when I have time to type all of those pages).