Thanks Norm, for the two resources for additional information about the Brown Family line. I will look for these on my next visit to the Dallas library.
I found the death date for Noah Brown in an item written by Charles Martin Ward, Jr. "Carpenter Descendants of John Howland in Tennessee", as published in Feb 1995 in "The Mayflower Quarterly", Vol.61, No. 1. And upon reading it again maybe Charles Martin Ward's wording was misleading. Speaking of Hannah Brown he says,"Her father, Noah Brown, was dead by May, 1776 and her brother, Noah Brown, Jr., was appointed her guardian on 28 Apr. 1777." Mr. Ward's reference for this sentence is listed as "The Mayflower Descendant, "The Estate of Noah Brown of Attleborough, Mass." Vol.21 (1919), pages 128-129. So I do not really know if Noah Jr. was appointed guardian because Hannah's father died in 1776, or if her mother, Deborah (Wilmarth) Brown died in 1776 and her father, Noah Brown, died even earlier.
I have not yet read the referenced article in the "The Mayflower Descendant", but plan to search through it soon, as well as some of the other references listed for that article, plus the two that you have mentioned. Thank you again.