Grain of salt duly noted. I suspected the son James you mentioned really belonged to the Middletown or Shrewsbury Laytons, not Freehold where Sam L & Janet O L were living.
Stillwell's Historical Miscellany Vol. 5 thought Rebekah(sic) could be a child (or grandchild) of Samuel's because he found a marriage record:
"May 1, 1727, Rebekah Layton, spinster, and Christopher Morris, cordwainer, both of Monmouth County, Samuel Layton, surety"
Probably not enough time elapsed for her to be a grandchild.
Thanks for your thoughtful answers.