Searching for Ryans/Ahearns/Heffernans

Looking for any help with my search:

Patrick Ryan was my great great grandfather. He married Margaret Ahearn. (Margaret Ahearn's mother was a Heffernan.)

The story I've heard is he and two brothers were very active in the resistance. Patrick wrote to "incite the masses". Evidently he and his two brother had to leave Ireland with their families very quickly. Patrick and family went to New York. A brother, name unknown, went to Chicago. Another brother, name also unknown, went to Australia.

The story I recently heard was that the Ryan/Ahearn marriage was arranged because th two families lived next to each other.

Patrick Ryan born 1847 arrived in US 1890 (may be 1880) died 1895

Margaret Ahearn Ryan born 1852 died in New York 1915

   Margaret's parents John Ahearn and Margaret Heffernan according to her death certificate from New York

Children:

John Ryan born Thurles October 10, 1878

James Ryan born Thurles 1880

Margaret Ryan born Thurles 1881

Mary Ryan born Thurles 1884

Julia Agnes Ryan born Thurles 1885 baptised Oct 12, 1885 Sponsors Rody "Aherne" and Mary Dwyer

  Believe it says Asch Diocese of Cashel   Parish of Anacarhy Reissued certificate from 1945 Name on certificate is Margaret Aherne

Bridget (Della) Josephine Ryan born Kilaptrick, Cashel, Tipperary Jan 14, 1888

      We have a reissued birth certificate for Bridget.  We always new her as Della.  When she applied for retirement she had to have her birth certificate reissued.

Ella Ryan born 1891 in New York

Brother 1 - Chicago

My great aunt Della (Bridget) attended a ceremony dedicating a park to him in Chicago area. Know nothing else about him. Chicago historical society could find no record.

Brother 2 - Australia

Just recently discovered this story and know nothing more

I have hit a wall and can find nothing on Patrick Ryan or Margaret Ahearn (Aherne) before arriving in New York. No absolutely nothing of brothers of Patrick Ryan.

Any help would be greatly appreciated