So the Wiki lists the following to make sense of the family tree:
Brother 1 — Luke and Jud Kane's father
Brother 2 — Bo's father
Brother 3 — Daisy's father
Brother 4 — Coy's father
Brother 5 — Vance's father
Brother 6 — Jeb Stewart's father.
Brother 7 — Jesse Duke
But what if it was like this:
Brother 1 — Luke and Jud Kane's AND Coy's father
Brother 2 — Bo's AND Vance's father
Brother 3 — Daisy's father
Brother 4 — Jeb Stewart's father.
Brother 5 — Jesse Duke
No place did they say that Coy was Luke's cousin or that Vance was Bo's cousin all they said was Coy AND Vance were cousin.