I am indebted to you all. The articles were sublime, and the hints are all helpful. John R. Marwick's nieces are somewhat accounted for (or are they?), his brother was in Australia by 1870 and even 1863. One sister remained in England and is the mother of the out-of-towner "Mrs Russell" alluded to in one of the detailed obituaries.....which leaves an elusive sister Mary Ann who migrated to the US either as a widow or with her first husband James Earl and ended up in Australia as Mrs Barnes to live with her other brother, her death certificate indicates a deceased daughter!
Some much to digest, but I am so grateful of the generosity displayed here.
Thank you ALL so very much.