Anne, I am fairly new to wikitree, but I am not new to genealogy. I have been doing it for decades.
You said: "Once again Last Name at Birth: "This is the formal name that would appear in official documents at the time of birth, unless they were amended or corrected soon after birth" (src: the style guide")"
This makes perfect sense for 20th century birth certificates, and it makes perfect sense for 19th century immigrants, but it cannot apply as an unbreakable rule for pre-1700 and medieval profiles when spelling was not standardized and irrelevant to the clerks recording baptisms.
The Style Guide also says:
LNAB: This field could also be called Proper Last Name, Surname, or Maiden Name.
It also says “In those cases, we recommend choosing the spelling that is most recognizable to modern descendants, e.g. "Winslow" rather than "Wynslow" or "Winslowe."
Why are these in the style guide? Because it emphasizes that in time periods where spelling is not standardized that there needs to be some leeway and common sense applied to choosing a LNAB.
I served as the genealogist for the Eaton Family Association. When then the baptismal record of Francis Eaton of the Mayflower was published in 1997, we did not change his name to Francis Eatton of the Mayflower. All of his descendants know him as Eaton, the Mayflower Society calls him Eaton, and all published Eaton family genealogies call him Eaton. Similarly, John Eaton of Dedham did not become John Eton of Dedham. It would not make sense to change two hundred years of genealogical research.
Anne you use this collective ‘us’ like everyone on wikitree agrees with you, but I am not sure from the responses this is true. It is not OK to have “6 different last names for children of one parent” especially in a well-documented pre-1700 family group. And, I don’t think you can say a single spelling in one medieval parish record is a “buck stops here” answer to how you spell the name of an individual.
Names do change over time, and so occasionally it is completely appropriate for a child’s LNAB to not match the parents. But the general rule and guideline cannot be follow the parish record no matter what.