It is not, in practice, unusual to find multiple connections between two families. Boy meets girl, and their siblings also meet.
Well, I just reminded myself to research what might be such a loop, the Gruwell-Elliott loop.
I am terrible at calculating these degrees, but I believe that means Mary is my second cousin three times removed (or third cousin twice removed.)
So far I have discovered almost nothing about Isaac Gruwell, but it is possible he and Ruth had a son named Daniel who married his first cousin. I did find one report, as a caption for an image of Ruth Elliot Gruwell Potee, that she moved to Iowa with Isaac, and after his death returned to Ohio, although when she gained the surname Potee was not explained.
Ruth, Phoebe, and John’s father was Isaac Elliott (1787), and he had a brother named Benjamin Elliott (possibly 1778), who had a son named Benjamin Elliott (1803), who married Sarah Gruwell (1804)! This would mean cousins married people who, at least, shared a surname. And, again, another possible family from which may have sprung Daniel Ira.
I shall not be surprised, as I continue to pick at this tangle, to eventually find there is a close crossing. But even if not, it is still a very interesting puzzle to figure out whose spouse is related to another.