Not being helpful, I know. I'm sure they'll surface but you musn't mind us enjoying the fact that you only wonder if she came from Ireland. In this week of St. Paddy's day, when so many of us are up to our eyeballs in Irish family history, it seems obvious that your Patrick Docherty and Isabella Kelly could have originated no-where else, even if not both first generation immigrants, though births c.1847 suggest they arrived with the first wave of the great post famine diaspora.
Wishing you all the luck of the Irish.