I'm revisiting this thread to share the little bit of new information I've found.

I was able to find a passenger record for a Louis Silva dated in 1867. My only concern with this date is that his first son was born in 1867. He could have sent his wife ahead of him, but I can't find a passenger record for a Bridget Delia Silva (nee McCann). I suppose it's possible they could have met in England when both were intending to immigrate? Aside from meeting in the US or in Liverpool, I'm not sure how they would have met and he was from Portugal and she was from Ireland.

Still no marriage certificate neither in the US or in England/Ireland/Portugal.

Any other suggestions for a search? Thank you!