This is the only source I've found other than personal trees:
https://books.google.com/books/about/Descendants_of_Giles_Newton_I....
But none of the sources, trees or book, indicate Elizabeth Terrell had more than one husband, but it definitely seems this is either the same woman or people have gotten them confused.
Based on what little documentation I can discover, I don't believe Elizabeth (Terrill) Baker is the same person as Elizabeth (Terrell) Newton and that they've just become confused in some trees.
Most of what I've seen on Elizabeth (Terrill) Baker consistently shows her maiden name as Terrill and her dates in this range:
BIRTH 28 JANUARY 1734 • Buncombe County, North Carolina, Colonial America
DEATH 1785 • Chowan County, North Carolina, Colonial America
Whereas Elizabeth (Terrell) Newton shows
Date of Birth: January 28, 1735
Chowan County, Province of North Carolina, Colonial America
Death: October 15, 1807 (72)
Baker always has the Terrill spelling and Newton always has the Terrell spelling.
I think the nearest of their maiden names and dates of birth is the likely source of the confusion. It seems pretty conclusive who Elizabeth (Terrell) Newton's parents were but nothing seems to validate them as the parents of Elizabeth (Terrill) Baker.
They definitely need some notes and/or documentation in their About sections to clarify things.