General and specific information(lots of info included) re: John Ryan and Julia Campbell of Dublin

Hello everybody and thanks in advance for taking the time to look over this! :)

I came across this entire project whilst watching Tar Abhaile on TG4! 

I am looking for information regarding my ancestors who, according to to a Scottish marriage certificate (which I can upload if need be) originated from Dublin but the problem is it was some time ago! 

So,

My 3 x great grandfather: John Ryan born 1833 approx in Dublin married a Jane Wilson in Cadder, Scotland in 1855. I was very lucky in that they married in 1855 as only in that year did the Scottish/British gov declare place of birth including ''town''. So it states that he was born in the COUNTY of Dublin. It also mentions that his parents were: John Ryan (deceased) prof. Master Tailor and Julia Campbell (deceased). Now if accurate, John (jr) was 22 at the time of his wedding and by this time both parents were dead - I can only presume that his parents died in Ireland as Scottish records are pretty good and there is no official death record for either of them and the official death records (off the top of my head) run back to 1845 in some instances as do censuses. There seems to be no evidence of any brothers or sisters with my John in Scotland whatsoever. Possibly he never had them if his family died young or possibly, there's something a bit more sinister? The reason I say so is (slap me if i'm going a bit off the ball and crazy here) I personally feel there was a difficult relationship with the mother (Julia Campbell), the reason being. John went on to have about 10 children and John's children were all easily producing 10 of their own on average lol however NOT ONCE, NEVER has the name Julia been passed down to any of John's children or indeed John's children's children but the name of the mother was certainly known to her ''grandchildren'' as when John died himself in 1897 it was one of his youngest sons who was the informant of death and he was able to provide the mother's name on the death certificate.

On my searches, I came across a John Ryan born in 'Ireland' who was of the right age living in army barracks in Scotland at the time but there's zero evidence to suggest it's the same person. 

My wish is to find out at least which townland/parish the family originated from if it was indeed Dublin however I tend to think that they were likely from Dublin but parents had originated from elsewhere. 

Another avenue which causes confusion is that when John married Jane Wilson in Scotland, it was in a protestant church but my family to this day are ''catholic'' however without wanting to ''be that elephant in the room'', the name Campbell was quite a common protestant name in the north and so I wonder if John Senior Ryan had possibly married a protestant girl, or maybe converted for aid during the hard times? Or possibly, if he was a master tailor, was protestant due to the anti-catholic stigma of the time?

I have tried unbelievably hard to track down as much about this family as possible however i'm getting nowhere before John. I have pictures, certificates of his children, I have made contact with many of my wider extended family that started with him but not one of them has a clue about this guy or his parents. 

Anyway,

Any advise or help would be gratefully appreciated as would any speculation over the above regarding religion, the fact the name wasn't passed down etc.

I hope you are all well!

Scott Ryan!

PS: Isn't it funny how life goes round in circles as I myself now live in Dublin!

I have included an upload of the marriage certificate for John Ryan (which is awful to read!) and a picture of his son, my 2x great grandfather Alexander Ryan (by the Al Capone look - is definitely somewhat the son of a tailor!) sadly however in Scotland every single one of them ended up as miners and farm labourers.