This is wild speculation, but sometimes that's what it takes to break through a brick wall.
I'm wondering about this John F Fielder from the 1860 Ozark Co, MO census. He's living with his mother and younger brother next door to Samuel Dunigan, Sena's brother. I'm not sure who James Dunigan is and how he fits into Sena's family.
1860 United States Federal Census Ozark, Missouri
#89 Samuel Dunigan 25 m w potter $0r $45p TN Sarah Dunigan 33 f w TN Alfred T Dunigan 15 m w MO Missouri Dunigan 11 f w KY William H? Dunigan 9 m w KY Samuel L Dunigan 5 m w KY James R Dunigan 3 m w MO
#90 Jane Fielder 39 f w farmer $0r $75p KY John F Fielder 19 m w KY William L Fielder 4 m w MO
#91 James Dunigan 20 m w farmer $0r $45p KY Elizabeth Dunigan 17 f w KY
There's such a large difference in ages between John F and William L Fielder, I'm wondering if William L could have been from a second marriage and the John F is really your John F Price? Also, is it possible that Elizabeth, wife of James Dunigan, was also a child of Jane, and a sister or half-sister to John F? I said it was wild speculation, but I think that you should try to find information on Jane, John F and William L, as well as Elizabeth ??? Dunigan.
In 1870 John and Sena are living next door to Rachel Dunigan Risenhoover and her family. Rachel is Sena's sister. Next door to the Risenhoover family is a Jane Roberts, age 49 born in KY, and her son James, age 6 born in MO. Could that be Jane Fielder after another marriage and could James Roberts be the brother, Monroe, of John F Price from the 1880 census? It's really going out on a limb, but again I think you should look into Jane Roberts and son, James.
I've tried to find Jane in the 1850 census as a Price or Fielder as well as in 1880 and later census years as a Roberts without any luck. I haven't had time to follow up on James and Elizabeth Dunigan or to try and find William L Fielder or James Roberts in later records.