I originally developed this theory.
Over 30 years ago, my cousin Mitchell Oliphant shared with me some of his correspondence with Eula Stewart Oster (Thomas Otto Stewart's daughter). In a 1957 letter to Mitchell, Eula relates some Family Lore on Martin Lafayette: the story goes that he was born in Georgia or Alabama. His mother died when he was a "youngster", so his father sent him to Mississippi with another family (intending to join him later). Martin Lafayette made it, but the father never showed up.
I never found records to support any of this, so I discarded the Family Lore as false and began searching far and wide for Martin Lafayette -- in pretty much every state east of the Mississippi River. Eventually, I happened upon this Lazarus P. in Illinois who had a son Martin L. (born just two years before my Martin Lafayette). RIght before the Civil War, Lazarus P. moved his family to Sebastian County, Arkansas and, not long after that, Martin Lafayette enlisted with the Confederates in Corinth, MS. My imagination filled in the gaps: concluding that this Illinois Martin L. MUST be my Martin Lafayette. Embarrassed by his Yankee heritage -- so my backstory became -- he must have concocted this white lie that he was an orphaned Georgia boy for his friends and family. Soon after I linked Lazarus P. to the Tribe of Lazarus (in Pennsylvania) and I was off and running.
Both the 1850 and 1860 federal census reports show a Martin L. to have been born in Illinois to Lazarus and an unknown wife. These two records -- coupled with the history of this Stewart branch making their way from PA to NC to TN to IL and (finally) to AR just before the Civil War -- combined with the known fact that Martin Lafayette settled in Yell County, AR after the Civil War -- became the foundation for my theory that Martin Lafayette was a Tribe of Lazarus descendant.
But my recent FTDNA Big Y-700 and autosomal test results have blown this theory out of the water. Also, I recently learned, from Jacob Stewart (via David Stewart), that when Martin Lafayette enlisted in Corinth, MS at age 18, he gave Newton Station, MS as his residence.
In light of all this, I recommend disconnecting Martin Lafayette from Lazarus P.