The Find a Grave records are confusing for both Jedediah Hills and Phebe Barger. I think Jedediah's surname on the Findagrave probably comes from "The Barger Journal" reference to him as Jeremiah Hills Ison Horton. What Ison has to do with anything is beyond me. Perhaps the entry was implying a stepchild relationship with John Horton. But the fact is that the probate record says Jedidiah Hills (not Jedediah Hills Ison Horton) was deceased by the date of the probate record in 1820.
Solid documentation for Jedediah Hills, not Jedediah Horton.
Regarding Phebe, Jedediah's wife, I find no other mention of her as being Phebe Barger except in "The Barger Journal." Clearly, Jedediah's wife was named Phebe. She is called Phebe Denny in the probate record. She must have been remarried since Jedediah's death, since she wasn't called Phebe Hills in the probate record. Phebe Barger 1786-1830 is listed in a 1915 listing of headstones at the Adams Corners Cemetery "a daughter of John and Martha Barger," but no mention of a married name Hill or Denny, so hard to say if she is the Phebe that was married to Jedediah HIlls and a Mr. Denny. The only fact that makes me think this Phebe Barger was Jedediah's wife, is that the person she petitions to be guardian of her children, Cornelius Tompkins, I believe to be her uncle, brother to her mother Martha Tompkins. Makes sense that Phebe would want a relative to be guardian to her children.