The Mysterious John Beaird

Nan Harvey just found a marriage record for Eleanor/ Elinor Fisher and John Beaird. I suspected they had married in the late 1780's or early 1790's in Tennessee. I was surprised to find out that they had married in 1799 in Pulaski County, Ky. I had understood that at least one of their children, John Beaird Jr., was of age by 1809 when  his father John Sr. died.
My relationship to the Beaird family is through my ancestor Catherine Fisher who was the sister of John's wife Eleanor. I've only found a couple of references to Catherine Fisher/Forgey in records. I've never been able to find anything giving her age. I found an estimated year of birth for her sister Eleanor of 1765. Another sister Mary Fisher/Steele was born 18 January 1758.
 John Beaird's family being more prominent he does appear in several local histories. I am hoping to find more info about my own family by following these collateral lines.
The newest discovery of  a marriage record for John and Eleanor does raise some questions. Was Eleanor John's first wife? I had suspected that John and Eleanor were neighbors of  my ancestors' Hugh and Catherine in Knox County, Tennessee, but now it looks like they were not married when they lived in Tennessee. It does look like they may have had a common law marriage before the official marriage in 1799, because it is suspected that their daughter Harriet was born to them in Tennessee.
I also found out that John Beaird sold his Flat Creek Knox County, TN property in 1797; when he was living in Lincoln County, KY. This was unexpected too. According to family tradition the family left Tennessee in 1801 for Randolph County, Illinois. The story also states the Fisher in-laws accompanied the Beairds in 1801? Did they really travel together or meet up later? Evidence does seem to point to a relationship between them in Tennessee. Maybe there was a common law marriage, and out of wedlock births?  I've found references to John Beaird living in Wayne County Ky, Lincoln County, Ky, and Pulaski County, Ky.  Apparently this is because the area he was living in was Lincoln County when his first settled there in 1797. This same area became Pulaski County, Ky in 1798 , and in 1800 it became part of the newly formed Wayne County, KY.  So lots of jurisdictional changes occurred in a short time. It does appear they left Kentucky for Illinois in 1801. I don't know whether the Fishers did the same?
I was also a little confused about where the Beairds and Fishers settled in Illinois. It appears the Fishers settled in Randolph County, and the Beairds in neighboring St. Clair, Illinois.  John Reynolds described the place the Beairds settled as 4 mile northeast of Kaskaskia, Illinois. The Fishers lived in the Ellis Grove area a few miles away. Now I am getting a better picture of where the families lived and when. It might be helpful to do some research in these new jurisdictions, which might produce more Fisher family documents.