What has also been established is that someone of full age got married by Licence rather than banns, and had guardians who consented to the marriage.
(I wonder if she was tied by some inheritance to having somebody's consent in order to marry?) Maybe you should contact the church and ask if they have any idea why?
http://www.clontarf.dublin.anglican.org/ (Noticed they are on Twitter?

- what next?)
The minute books from the parish do exist for the right year, so there might be an answer to some of the questions these facts raise.
Also, the name Clontarf turns out to be where Jessie herself married, to everybodies surprise.
Also, according to Burke's peerage, John Rawson of Clontarf was the only holder of the only title Clontarf in The Irish nobility. His grandaughter was therefore a Lady Ann, Daughter of Lady Clontarf, (In the right time bracket) The Daughter married into the Guinness family. ( possibly knon locally as the ould clontarf wan and the young clontarf wan..

)While Jessie's US census returns give her birthpace as Scotland, there is no reason why her grandmother, Lady Ann should not have been Irish, given that the family tie her to the name Clontarf. There are several contenders for Lady Ann amongst the local families with Clontarf Connections, interelated closely to the original Rawsons. Lots of local rellies for Joe ...who I see already thinks it is the purveyor of pints...!
Jessie being born in Scotland, but daughter of an Army officer could have been visiting relatives or on a posting in Dublin with her family.
Jane Rose is a local name in Clontarf,but I don't know if they had any titled family. At the same time, this story has travelled five or six generations, so parts of it may be wrong on dates.
When Joe gets the photo of the portrait - and maybe the other items - and puts them up here, maybe the date of her clothes will sort that one out.
There are good guides for silver and gold jewellery marks on line too. It is possible that lady Clontarf was the first owner, and she passed them to her granddaughter. But this is speculation.
For Joe the problem is with the slender info he has on Jessie, getting her birth cert on Scotlands People is like trying for Mary Murphy born Ireland c. 1828, especially as the population was so vast!
Maybe Shane could try Thom's for the Witnesses - Jane Rose and Edward Burke? Any Dublin Rose? Also once Joe has the photos we might get more ideas to help him. Hallmark,I don't know anything about The Roses re Title - did they have one? On your thinking Jessie's mother's maiden name might be Rose...
One possible one to check on Scotlands People Search.
I accept totally that the Clontarf wedding is fortuitous and they may all be from some out post of the Empire with a Clontarf sounding name...
Monica, I know why you said you were loosing sleep on this one! I would love to get it sorted for Joe's Mother and Aunts - I keep on thinking of that wedding dress...is she wearing it in the portrait? And hope Joe has found Clontarf Church on Google Earth. Nice spot to Marry in.
Shane, Joe's family oral tradition says the ring etc came down by the female line, but if in one generation there were no girls, then it might be the male line, which is why we are trying for both!