William J Howard death certificate is here:
There is a John Howard son of Seth Howard in the 1850 Bedford TN district 23 Census may or may not be him. This Seth Howard is not the same Seth Howard that bought up a big chunk of Mrogan, Benton, and Camden counties in the 1830's and 1840's.
FWIW see this page http://mhrising.com/ozarks%20families/howard_family.htm for that tree which seems to be predominatly from South Carolina via Kentucky.
There appears to be common thread of family origins in Bedford County TN this includes the Allison's, Dorman's, Kesner's, and Howard.