Hello again
I think that there may well be more than one William Robinson mainly because he did not leave anything to or even mention his children (Mary) in his will not convincing one way or the other, it could be a family fall out. Also there is a slight discrepancy in dates of death between 21st and 27th, though this could easily be an admin mistake. Perhaps I have the wrong William as the father of the Mary that I am following.
There also seems something odd about the names of the sister in law, one would expect that her surname, at some point, would be Robinson. I have not been able to find that,yet.
Still looking
Best wishes
Octo