I found Harrison Poindexter and Jane Clark on a marriage index in Greene Co., Illinois. They married 30 December 1835. If you haven't already, you might wish to pursue getting a copy of their marriage record; it may provide more details. I could not find it among the digitized images.
"Illinois Marriages, 1815-1935", database, FamilySearch (https://familysearch.org/ark:/61903/1:1:Q292-DNMM : 14 February 2020), Jane Clark in entry for Harrison S. Poindexter, 1835.
If Jane's ages on subsequent census records are accurate, they married when she was a child-- as young as nine, as old as 13. He was about 10 years older than she was.
While Illinois did have an indigenous population, most of the Indians had been forced from their homes south to Oklahoma by the time of these records. And given that Harrison was born in Kentucky and Jane born in Virginia, if they were indeed Native American as the 1860 census suggests, they were not native to Illinois-based tribes. But similar to the indigenous populations of Illinois, the Indians of Virginia and Kentucky were also forced out of those states long before these census records. Harrison and/or Jane might have been Chickasaw or Shawnee which were known to have lived/travelled through Kentucky and parts of Virginia.
Going back to Florilla/Flora, she died by late 1880; photography was pretty rare at that time. Not impossible, but rare. Perhaps if they'd lived in an urban area, there might have been a chance for a photograph. But she died, probably, in /near Kokomo, Indiana. I have been unable to find a burial for her. She is not buried in the same cemetery as her husband.
