Margaret Terrill (Watkins) - Need Help with Parents

I came across this connection on my son's parental side of his tree. Nothing in the profile for John Gassaway Watkins indicates he had but two wives, neither of which was named Mary Katherine Watkins and there's no daughter Margaret listed. Need documention noted in this profile for this Margaret parents, something other than just what someone has in their tree that got loaded in a gedcom. From what I can see, this Margaret isn't connected to her correct parents and that makes all the pathways that include her possibly incorrect. It's not my direct line, so I'm hoping one of the direct descendants can sort it out and make any needed corrections.