Hi Jan Don't know if this will help or confuse matters, but, my grandmother's family were Akerleys.Her Akerley ancestors were mostly born and lived in Queens County, New Brunswick.My grandmother was born in Saint John, N.B. I haven't done extensive research on them as yet but I understand that this particular Akerley family came from New York to N.B. as loyalists.I was in touch with the Queens Co. Historical Society at Gagetown, N.B.The director Bruce Thomson sent me over a list from their files of the family of James Akerley (direct ancestors of my grandmother).There is a daughter named, Mercy, however she was born around 1810.This was the only Mercy I have found so far in my research other than the one you mentioned (William's daughter).Here is the list just in case you can make use of it:
James Ackerley, b. 4 May 1767 Southold, NY, d. 1855 Wickham NB.M. Susannah Dixon of Wickham c.1792. Children: 1. James Jr. b. 16 May 1794, m. Elizabeth Dingee 28 Mar 1818 2.Daniel b. 1 Apr 1796 m. Sarah Algee 1824 3.Isreal b. 1 May 1798 4.Titus b. 17 May 1800 5.Charles b. 10 Apr 1802 d. 27 Jan 1887 age 85, m. Jane Mott 6.Joanne b. 5 Apr 1804 7.Susannah Elizabeth b. 21 Apr 1806 8.Miriam b. 11 Aug 1808 9.Mercy b. 20 Sept 1810 10.Richard Clark b. 11 Aug 1812 11.Obediah b. 25 Dec 1814 12.Oliver b. 15 Jan 1817.
By the way, my grandmother is descended from James Jr and Elizabeth Dingee.Hope this helps in some way