Firstly, it's a pleasure to help - we enjoy this on Rootschat. My only other 'productive task' at the moment would be cleaning!
Secondly, experience tells us that some family stories are based on the truth but occasionally are enhanced.
In this case there is some evidence recorded so that is where you have to begin.
What is known:
The censuses have births in Ireland.
They married in an Anglican church - the norm at the time - but the children were baptised Roman Catholic.
You have baptisms from Birmingham - mother Carlton.
Frances' baptism is in the Manchester Catholic indexes - you have to enter names separately
http://www.mlfhs.org.uk/data/catholic_search.phpFrancesca Donoghue 1870 baptised St. Wilfrid, Hulme
Ricardi Donoghue 1870 Father of Francesca Donoghue St.Wilfrid, Hulme
Emmae Carlton 1870 Mother of Francesca Donoghue at St. Wilfrid, Hulme
So Carlton is used again.
On his marriage, there is no suggestion that Richard is already in the military , although he may have been attached as a civilian tailor - I don't know the proecedures.
Their addresses on marriage are, from what I can see in street indexes, in adjoining areas where there was a high Irish population in Manchester.
Looking at the marriage certificate, the signatures of Richard and Emma look very similar in style, I think
We know from Richard's army record that he was from St Mary's parish, Limerick.
We don't know where in Ireland Emma's origins are but family story is Dublin.
One would imagine that the Four Courts references would have some particular meaning - it would be an elaborate ruse otherwise perhaps.
As I said earlier, if she did change her name on marriage, perhaps she thought she would have to stick with that for her children's births. However, again, I feel that it would add to this exciting story rather than never be mentioned to her descendants.
best wishes
heywood