I have been tracking your web of confusion for days, keeping careful notes, and then, without having hit the save button, the computer crashed..... so most of what follows is from memory:
Your Francis had two sons born in Nova Scotia.... they have delayed birth registrations showing that at the time of their birth, Francis was a minister. One did not know where Francis was born, the other stated that Francis was born in St. Ferdinand. The son that died in Enderby BC shows Francis's birth as on a British ship....? Going back to the Nova Scotia records.... one spells Francis' middle name as Xavier, and the other as Exavia, so that could explain the middle initial E on his grave.
If you haven't seen these birth registration, they are fully readable at
https://www.novascotiagenealogy.com/ . Just put in the surname Rouleau, and they are the only two births to come up. Note that they are multiple pages, so don't miss them all!
I was tracking a Francis/Francois/Frank Xavier Rouleau born to Ignace Rouleau and wife Marie Fontaine. Francis was baptised in 1849. If this was him, he was married once before marrying Hannah. He had a sister (I think it was Josephine) that married into another Rouleau family, so I was on the hunt to see if Ignace was a brother to Joseph to explain the connection to those brothers of Rouleauville, Calgary. Maybe they were actually cousins, or brother in laws?
There was a Joseph mentioned on either Francis' baptism, or Ignace's marriage, but I can't remember which!
Sorry if this is all confusing, but I thought I should post before the bits in my own memory vanish just like my notes did! When I stop fuming at my computer, I'll sift through it's memory to see if I can find anything of value that I was looking at.