Unfortunately, the census doesn't list relationships at that point in time.However, Susan was listed as a DeLauzon but she also was listed as born in Newfoundland which points to the idea she was related to the Picot's.So there might be something there.Also, I doubt Emma would have been involved at all unless Edward the son was a relation.Otherwise, she would have no standing I would think as regards to inheritance, etc.
Edward was listed as a book seller.Nathan as a cooper.One of the daughters, Sara Picot, listed as born not in Newfoundland, but in Canada.Then I just found an entry from The Ontario Register in 1857.It listed Nathan Picot as being in Cobourg, North'd.It should be him as he is listed as a "cooper" living or working on Elgin Street.
So far, all I can find.
I will re-read what you have written and then go from there.There must be a record of marriage somewhere. Will get back later when I have looked some more.