These people were descendants of settlers in the Dutch colony of New Netherland. They almost certainly spoke Dutch as their first or only language (although they lived under British colonial rule and they were not necessarily of Dutch ancestry). Their names were mostly Dutch names like Jan, not English names like John.
Neeltje Schenck did marry Jan Wyckoff, Since Jan was a son of Cornelis, he probably used the patronymic name Cornelisz or Cornelise in addition to the family name Wyckoff. As you apparently have seen, American writers have made a practice of changing these names to English forms for reader convenience, so they would convert the name Jan Cornelisz to a first name of John and a middle name of Cornelius. We do not do that in WikiTree. Instead we use the names that people were known by during their lives, not the names that their descendants use or that bookwriters decided would be more convenient for modern readers.
Neeltje Schenck and Jan Wyckoff had a daughter Neeltje who does not yet have a profile in WikiTree. (All of the children of Jan Wyckoff are believed to be children of the second wife, Neeltje.) The main source (Early Bergen County Families) cited in the profiles for the parents of this child does not include any details other than her name and the fact that she was mentioned in her father's will. But being named in his will means she was alive in 1746.
Ancestry Family Trees are not reliable sources for WikiTree profiles, although many members like to cite them.
What information do you have about this Neeltje Wyckoff you are interested in? (Surely you have more details than the name of Johnson.)
