I can't tell you how much you have help me not only find things but validate.Last night I had the thought to look on ancestry.com the Lowndes, Alabama 1850 for a Lazerus Smith and I found exactly what you have found.It is refreshing to me to have someone else see the same things that I am seeing.Being that you and I are both not related to the Gray family (this is one of my daughter-in-laws's family lines, though I believe I have come to know the family a bit, the fresh eyes and critical thinking really helps out.
I look to see if a John Gray was possibly on the 1850 Census for Lowndes, Alabama but he was not.I remember you finding some John Gray land owners and I can see that there are a number of them but have not found one who matches up with his birth date (varies from census to census the date of his birth).
I did note that on the 1860 Census in Union Parish Lazerus' wife Eliza is listed as being born in South Carolina as is he, but on the 1850 Lowndes, Alabama Census her birth place is given a Alabama.I am certain that one of those is incorrect.At https://www.familysearch.org I remember finding a Lazerus Smith married to an Eliza but the marriage date was I believe 1846 or something like that and long after she born the children which appear in the 1850 and 1860 census records.Perhaps they were married in Alabama and I have not found it yet or they were married elsewhere.
I have been to Louisiana website page looking for possible probate records and whatever they might have posted and find nothing.This will probably be another thing I need to look at microfilm and be at a library for.
One other thing I noted is that there is a Plawson or is it Slawson (ancestry has it transcribed as Slawson???) on the 1860 Union Parish Census with Lazerus and family.I saw a separate Plawson or Slawson family when I look through the 1850 Lowndes, Alabama Census in another household and so I am wondering if this surname is related to Lazerus' wife Eliza.
Many, many questions but I do believe that the mother of Martha, Elizabeth, Adolphus and probably the mother of Julian (note that in the 1850 Lowndes County, Alabama census Lazerus has a daughter (sister to Lydia) named Julia A.) and also the mother of Julia and Ardonia is Lydia Smith.I believe that the Lilley who shows up on the 1870 Union Parish Census with John Grey, John Grey, Jr. (most probably son of Sarah Matthews Wood Phillips Gray and her 2nd husband Lewis Phillips) Julian and Ardonia should really be Liddy rather than Lilley and it is the census taker's error.Certainly I can't prove that but there are to many things which have come together (finding Martha Evada Gray Walkup's grandson and his research reports being sent to me) that indicate what you and I have thought all along that Lilley on the 1870 Union Parish, Louisiana Census is the wife of John Gray even though there is an age difference between husband and wife.
Just a guess but I would not be surprised if John Gray had been married prior to his 25 Dec 1851 marriage to Mrs. Sarah Phillips.That I can not prove either since I have no idea who the father of John Gray is and Jim Walkup has no knowledge of who John Gray's father is either.
Thanks for taking the time to read my workup on the Gray Family.Again I can't tell you how much I appreciate your input.