Have you see this? Mentions Zebedee Mayhew, Digital Image 427, Document Pg 391, Does not give the mother's name but does confirm his Paternal Line https://www.forgottenbooks.com/it/download/NarrativeoftheTownofMachias_10544461.pdf
The only source I could find for his birth was FAG (1782) which is still uncertain but earlier than what you have on Wikitree. Because there is an image of a headstone it is best you have (as yet) to support his estimated birth date
https://www.findagrave.com/memorial/27037465/zebedee-mayhew
Here is his burial details
https://www.familysearch.org/ark:/61903/3:1:3QS7-L9FQ-3GNV?i=3335&cc=2242151&personaUrl=%2Fark%3A%2F61903%2F1%3A1%3AQKMB-BXY4
Banks in vol. 3 of his History of Martha’s Vineyard
https://www.familysearch.org/search/catalog/79188?availability=Family%20History%20Library
lists children of Nathan Mathew on page 320. He gives exact birthdates, so they were recorded somewhere. None is named Zebedee. But it looks like you could squeeze another kid in around 1776.