After months of wondering, I finally found the missing link connecting my original host family (Cheikh and all his daughters) to my new adopted host family (my fantastic neighbors). Which means I have figured out how I (as daughter of my first family) am related to myself (as daughter of my second family).
My 2nd host father's brother's wife's father's sister's son is my 1st host father. Said another way, I am my great uncle's son in law's niece, or the reverse, my uncle's father in law's great niece.
I'm still working on drawing the family tree of the entire village - it's already pretty overwhelming - but it's fun to see how everyone fits into the picture.