Whilst this may be a simple case of accident or stranger abduction I would certainly look more closely at the extended family, many of whom were, presumably, at the ranch. Newel Steed was a member of the Fundamentalist Church of Jesus Christ of Latter Day Saints (FLDS), the sect that was run by Warren Jeffs, currently serving life plus 20 years for child abuse. Warreb Jeffs is the son of the previous leader Rulon Jeffs and Merilyn Steed who, if I have understood the genealogy correctly, is the niece of Newel Steed. Although the Warren Jeffs case dates to the 2000s there was already huge concern about the activities of the FLDS at the time Vilate went missing. In 1953 there was the Short Creek raid where 236 children were removed from their parents due to concerns about the sect practices. All of this may be unrelated to Vilate's disappearance, but it certainly merits close examination.
On another site (which site rules mean may not be linked) there is a comment from a relative which says that some members of Newel Steed's family disapproved his polygamy, which he sought to keep secret (presumably because of the attitude of the authorities), and that there is a story that they sought to take a child of his to prove his paternity and polygamy - but took Vilate by mistake (her parents not being part of the sect). I have no idea if this is true but it should not be difficult for LE to trace the poster for questioning given it was only posted in 2019.
On another site (which site rules mean may not be linked) there is a comment from a relative which says that some members of Newel Steed's family disapproved his polygamy, which he sought to keep secret (presumably because of the attitude of the authorities), and that there is a story that they sought to take a child of his to prove his paternity and polygamy - but took Vilate by mistake (her parents not being part of the sect). I have no idea if this is true but it should not be difficult for LE to trace the poster for questioning given it was only posted in 2019.