Lennie Mathis of Water Valley (Mississippi), McKinney and Abilene(Texas)

     My favorite part of genealogy is the hunt.  I love searching for documents that prove links to ancestors.  My big downfall as a genealogist is failing to add the information to the family tree as soon as I find it.  
    Today, while perusing my files I realized the I had the obituary of Linnie Mathis Leggett.  As I re-read the obituary I noticed that it mentioned her place of birth (Water Valley, Mississippi); year of birth (probably incorrectly as 1864); the year her family moved to McKinney, Texas; the year of her marriage to William Pinkney Leggett; the year they moved to Abilene; and that she was survived by as sister.

Lennie Mathis Leggett

     Immediately I tried finding Linnie and her family in the census (remember I love the hunt).  I found a possible family living in Collin County - James Matthews³, wife Sally, daughters Lena, Laura and Alice.  Could this be them?  The age for Lena didn't quite match the obituary.  I could see how a census taker might mistake Mathis for Mathews so this might be our family.
     Since the obituary mentioned that she was survived by a sister, I wanted to see if her sister was Laura or Alice. Unfortunately her sister is identified as Mrs Tom Leggett.  Did sisters marry brothers?  I looked in the census for a Tom Leggett in the appropriate city and found a Tom Leggett with wife, Lee.  Things were not looking good.  So I looked in the Texas death records for a Tom Leggett hoping I might find a Tom with a wife Laura or Alice.  Success!  I found a mention of a Tom with a wife, Laura.  I found Laura's death record and her name was listed as Laura Lee Mathis Leggett. 
    After realizing that I had Lennie's death certificate I compared information.  Both Lennie's¹ and Laura's² death certificates show their parents as James and Sallie.  I am fairly certain that the 1880 census record showing James and Sally Mathews is Lennie's family.
    This has open a Pandora's Box.  
First, where are James and Sallie born.  The Census says, Georgia and Alabama.  Lennie's Certificate says both her parents are from Mississippi.  Laura's certificate says they were both born in Tennessee.   Georgia, Alabama, Mississippi, or Tennessee?  
Second, when was Laura born? The obituary says 1864.  The census says about 1870.  The tombstone says 1872.  The death record says 1872.  I would vote for 1872 at this point but I would like some more data.
Third, if Laura lived in McKinney, Texas and married William Pinkney Leggett who lived in McKinney, will we find a marriage record there?  My niece, Jayme lives in McKinney.  Guess who has a job.
Fourth, can we find more information about James and Sallie?

1. "Texas, Deaths, 1890-1976," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/KSBL-KX7 : accessed 27 Sep 2013), Linnie Leggett, 1936.

2. "Texas, Deaths, 1890-1976," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/KS1M-Q13 : accessed 26 Sep 2013), Laura Lee Leggett, 1945.

3. Year: 1880; Census Place: Precinct 8, Collin, Texas; Roll: 1296; Family History Film: 1255296; Page: 292A; Enumeration District: 029. http://search.ancestry.com/cgi-bin/sse.dll?db=1880usfedcen&indiv=try&h=40383085