Betsy, nice to hear from a Compo researcher. My G grandparents were Jennie Dunlop and William Compo, son of Thomas, son of Antoine. As you have figured out, Levi Compo's older sisters were Charlotte b.1845, Elizabeth b.1846 (my GG Grandmother), Lydia b.1848, then Levi b.1850 whose parents were Isaac Compo (son of John & Mary Compo) and Elizabeth Lacompt, our common ancestors.
Have always thought my GGG grandfather Antoine was a brother of Isaac (Levi & Elizabeth’s father) but could never find any proof. How have you connected the dots?