Valancy Stirling: played by Kristin Kreuk, Valancy realizes upon her 29th birthday that her family is hideous and her life completely stifled. She leaves home, causing quite a scandal, and sets out to do things her way.
Barney Snaith: played by Ewan McGregor, Barney is the town rascal--mysterious and always in his shirtsleeves. No one knows where he's from, who his people are, or just what he does for a living.
Abel Gay: played by Brendan Gleeson, "Roaring Abel" is a disreputable old drunk with a heart of gold.
Cecily Gay: played by Amanda Seyfried, Cecily is the daughter of Abel Gay and is wasting away of consumption. She had a child out of wedlock--rumored to be Barney's--and after leaving her family Valancy takes care of Cecily and keeps house for Abel.
And that's how Diana casts it! All images pulled from Google and Wikipedia.