I have reviewed all the books that I have for St. George, ME and I can't verify that Sally Stover b. 1815 is the daughter of Caleb & Sarah Stover. From what I have looked at it appears that she is their daughter but I can't find the proof. Also, it appears that Sally Stover married William Wall and I really can't find them in any Census records or the burial records from St. George, ME. I did find some family trees where they attached a Sallie Wall that was one of my relatives and not your Sally Wall.
Looking at the Census records Caleb Stover lived in St. George in 1810 but I found him in 1820 in Warren, ME. Perhaps the birth records might be in Warren. He later moves back to St. George.
These families lived somewhere around Wiley's Corner and the Clark family, I believe, was a different family from the ones that lived nearer to Port Clyde. If they are connected I haven't found it. My Clark's lived in Martinsville on the way to Port Clyde.
I also can't prove that Elizabeth Elwell was the daughter of John and Elizabeth. I have found some of their children buried in the Old Parish Cemetery but Elizabeth was not with them. I did ascertain from the Vital Records that she married John Odier (Odiorne). I also found in my newspaper (Records of Rockland from the Lime Rock Gazette and Rockland Gazette) that they had a child die on 23 Jan 1856 on Dix Island. I believe sometime later that year Elizabeth may have died as John remarries in the following notice:
Odiorne, John married 12 April 1857 at Dix Island Mrs. Hannah W. Elwell, both of Dix Island. Published 23 Apr 1857.
I don't know what city or town would have the records for Dix Island, Maine but you might find Elizabeth's death record.
Sorry I couldn't have been of more help to you in your search. If you have any further questions, please don't hesitate to contact me.
Joanne Clark Borden