Trying to apply a strict genetic test to WASP-hood, which is a sociocultural construct never used by the people to whom it is applied, is futile.
If one must be of non-Catholic British Isles descent to be a WASP, must one also be wealthy? Must one have attended an Ivy League school? Would a strong liberal arts college like Amherst or Swarthmore be acceptable? Is there a minimum net worth requirement?
Would the du Pont family of Delaware qualify as WASPs? They are of Huguenot French, rather than English, stock, and they came to America in the early 19th century, which is "late" compared to the colonial Mayflower settlers. Same story with the Rockefellers, who are of German ancestry and came to America well after the Revolutionary War.
Certainly not John D.'s father Bill, who was a traveling salesman (elixirs), abandoned his family, and was a bigamist under an assumed name.
John D. graduated from a business college.
His only son, John D., Jr., went to Brown.
His sons all went to Ivy League schools: John D III (Princeton), Nelson (Dartmouth), Laurence (Princeton), Winthrop (Yale, but expelled), David (Harvard)
The 4th generation includes John D IV (Jay) Harvard, Nelson's 4 sons: Dartmouth+Columbia, Princeton, Harvard, and Princeton; David's sons: Harvard and Harvard Medical (I don't know if his BA is from Harvard). The only exception is Winthrop's son, who went to TCU (so being expelled from Yale, and moving to Arkansas, must de-WASP you.
So by the time, WASP's began being called WASP''s they would have been.