Sorry about the mix up in my earlier post. I was mixing up the man living in Barry Co, MO with the man living in Howell Co, MO in 1870 census.

I do believe you may be on the right track. Here's how I see the census records that appear to follow the same man and two of his three wives and family starting with the two earliest marriages:

KING, JEFFERSON BUCK, NANCY 1835-10-15 002 0143 JEFFERSON

KING, JEFFERSON PAGE, MARY ANN 1845-04-18 002 0143 JEFFERSON

1850 census Franklin Co, IL - 10 Sep 1850

Jefferson King 35 M Farmer TN
Mary Ann King 21 F IL
Luticia J King 14 F IL
Eliza A King 12 F IL
Jno S King 9 M IL
Amand E King 7 F IL
Wm J King 4 M IL
Jas A King 2 M il

1860 census T4SR3E Jefferson Co, IL - 23 Jan 1860

Jefferson King 45 M Farmer TN
Mary King 32 F IL
John S King 20 M IL
Elizabeth King 17 F IL
William J King 14 M IL
James A King 12 M IL
Joseph A Lynch 9 M IL
Nancy J King 6 F IL
Francis M King 4 M IL

KING, JEFFERSON DAWSON, MARGARET 1863-02-23 002 0144 JEFFERSON

1870 census T5SR2E Franklin Co, IL = 1 Jul 1870

Thomas King 50 M W Farmer TN (age is off 5 years now)
Margaret King 36 F W TN
James King 12 M W TN
Alfred King 19 M W TN
Nancy J King 16 F W TN
Polly King 4 F W IL
Matilda King 2 F W IL

1880 census South Fork Twp, Howell Co, MO - 22 & 23 Jun 1880

Jefferson King W M 52 Farmer TN __ __
Magaret King W F 46 Wife TN TN TN
Polly Ann King W F 14 Dau MO TN TN
Matilda King W F 13 Dau IL TN TN
Elijah King W F 9 Son IL TN TN
Morgan King W M 5 Son IL TN TN
Ellander King W F 3 Dau IL TN TN

1900 census Spring Creek Twp, Howell Co, MO - 12 Jun 1900

Jefferson King Head W M Nov 1811 88 M 37 TN TN TN
Margot W? Wife W F Aug 1838 66 M 37 9 4 TN TN TN
Belle Lila Gr-dau W F Jun 1896 3 S AR Ind. Terr. IL