No your James can not be a son of my g-grandfather's brother James Breen who was born in Brookeborough in 1869. In recent research I found out that my g-grandfather's brother only married in 1896 and both he and his wife died in Belfast in 1899. I think they only had one infant daughter who also died in the same year.
There is a possibility that your James is a first cousin to my g-grandfather.
There is a Breen gravestone in the old graveyard in Brookeborough and your James' father could be listed on it.
The gravestone was erected by my g-grandfather's uncle Johnny Breen who lived at Owenbreedin (the farm where your g-grandfather listed as last place of residence).It reads as follows
PRAY FOR THE SOULS OF JAMES BREEN,CARRICKAHEENAN (B'Borough)
DIED DEC 2ND 1879 AGED 69 YEARS
AND HIS WIFE ANNE DIED MAY 4TH 1902 91 YEARS
ELLEN DIED JULY 18TH 1868 AGED 12 YEARS
MARGARET DIED MAY 14TH 1872 AGED 27 YEARS
JAMES DIED JULY 4TH 1877 AGED 25 YEARS
PATRICK DIED AUG 22ND 1895 AGED 40 YEARS
This Patrick could be your James' father.
He was a brother of Johnny Breen of Owenbreedin and could explain why your James may have been staying there before going to America. Patrick seems old enough. In Ireland the tradition was to name the first born son after the paternal grandfather so your James could well have been called after his grandfather the above James Breen from Carrickaheenan who died 1879. Just out of curiosity did your g-grandfather call his first son Patrick?
Johnny Breen (Owenbreedin) his wife Mary and their daughter
are also named on the above grave.
I hope this information is of some help. I am working on a Breen family tree and would be happy to share that and any other information I find out. Just send me your email.