According to your timeline, Sarah cannot be the mother of Elizabeth. She would have been 60 years old. Nor is she Elizabeth Addington. I've searched though Ancestry for every Elizabeth Addington I could find and none works out accordingly.
I did come across a Will where Sarah leaves a horse to Elizabeth, not Joel. I found mention that a Hannah Hubbard may be Elizabeth's mother with an unknown father. Peter II and Sarah were speculated to have taken in Hannah and Elizabeth as wards.
There was speculation that Petter II was the father, but Sarah was still living and I doubt she would allow her husband to be a polygamist.
I'm much happier thinking my relative didn't marry his Aunt. Please let me know if you have evidence to claim otherwise. I'm a direct descendent of the Bays family.
