I can offer a couple tips. First, the Vital Records of Wells Maine 1619-1950 page 170 gives the marriage date of Amos Cousens to Caroline Littlefield as 01 Jan 1808. The earlier filed intention of marriage on page 150 says they are "both of Wells." I can't find any reference of their parents, but your comment that Caroline was living with Israel leads to a possible answer. If you look at the 1850 US Census, Caroline is indeed living with Israel. On the same page is a single women by the name Catherine Littlefield born about 1785. On the previous page is a single woman named Lydia Littlefield born 1786 next to a Joseph born about 1829. This is quite likely Lydia Chick, widow of Samuel Littlefield and mother to Joseph Emerson Littlefield born 31 Oct 1828. Lydia's deceased husband Samuel had sisters Catherine & Mehitable, both born about the times we're looking for and their parents were Ithamar Littlefield (b. 28 Mar 1747) & Edna Davis (b. 14 June 1744). So that's my wild guess as to where you might go digging.