Do you have any dates? I'm still not certain if there's a connection. If there is, it would most likely be at the level of (for my own tracking) Sandfield's siblings (which I'm not sure of) or Zenophile's (Sandfield's father) siblings.
Some of maternal figures I've been able to track and they have Francophone names (doesn't mean they weren't converted, seeing as many of us know what happened to the indigenous Canadians).
The NY connection makes it sound unlikely that it's the same family, unless you have more info on Rhoda's parents? (Yes, I know you're looking for that, but a rumoured origin perhaps?)