Might Patrick and Hannah separated on unfriendly terms and might she have stayed in Ireland and been in service in 1911? Or does the family know for sure she went to America with Patrick?
Here is a possible match. The man's parents' names when he married match the ones you said.
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A tree at ancestry says that Patrick Power died in Rochester, no date and no source. I'll PM you with more regarding the owner and home person of the tree.
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Arriving in New York Aug 19, 1906, on the SS Etruria, NYC, from Queenstown
Patrick Power, 33, single, laborer, last residence: New Ross, destination: cousin Delia Malone, 228 Westminster, Rochester NY
https://heritage.statueofliberty.org/passenger-details/czoxMjoiMTAyMjc4MDcwNTA5Ijs=/czo4OiJtYW5pZmVzdCI7[New Ross was where "your" Patrick's son Kieran was born in 1906.]
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There were two Patrick Powers in Rochester in 1910. I think this is the man who arrived in 1906:
Boarding at 79 Hamilton St with Joseph Anise and family
Patrick Powers, 33, single, born in Ireland, arrived 1905, laborer at odd jobs, has begun the process of becoming a citizen
https://www.familysearch.org/ark:/61903/1:1:M5MV-9WY-------------
Note: this is the other man:
1910 boarding with his brother in law Henry Leach at 61 Cady
https://www.familysearch.org/ark:/61903/1:1:M5MN-ZVMThat man was still single in:
1920
https://www.familysearch.org/ark:/61903/1:1:MJGC-G1X1930
https://www.familysearch.org/ark:/61903/1:1:X78D-WTW1940
https://www.familysearch.org/ark:/61903/1:1:K31D-YHBHe might be the Patrick Powers who died 10 Sep 1952, in Rochester, age 79.
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Getting back to the man I think is "your" Patrick, there is this marriage:
Marriage 4 Oct 1917 in Rochester, Monroe Co, NY
Patrick Powers, age 42, son of Thomas and Mary (Welch) Powers. residence 533 Monroe Ave, a gardner, born in Ireland
spouse: Carrie Diehl, age 39, residence 9 1/2 Richmond St, Albany, parents: John Diehl and Evesina Rothaupt, both born in Germany. Witnesses: Miss Mary Diehl and Mrs Harry Diehl
1st marriage for both
https://www.ancestry.com/discoveryui-content/view/536032:61377?tid=&pid=&queryId=2a32a22c8b464f3b0aa7993d94c49056&_phsrc=Kkm59&_phstart=successSource------------
Here is that couple in 1930 and 1940:
1930 Census Rochester
at 557 Meigs St
Patrick Powers, b Northern Ireland, parents also, arrived 1885, naturalized, a machine operator, Kodak
Carrie Powers, b NY, parents in Germany
(his age, birthplace and immigration year doesn't match the 1910 Census or his obituary. Maybe his wife provided the information.)
https://www.familysearch.org/ark:/61903/1:1:X784-YH3--------
1940 Census Rochester
at 557 Meigs St
Patrick Powers, 64, janitor, 6 years school
Carrie Powers, 69
Mary L Diehl, 77, sister in law
all in same house in 1935
https://www.familysearch.org/ark:/61903/1:1:K31W-5QJPatrick Powers, husband of Carrie died 22 June 1953 in Rochester.
Here is his obituary from an OCR copy of the text. The paragraphing is mine.
Patrick Powers, 78, Dies;
George Eastman's Gardener
Patrick Towers, a 78-year-old son of Ireland who turned down a job as a New York cop in the 1900s "so he could stay honest,' died here yesterday (June 22, 1953). He was once a gardner and private policeman for George Eastman.
Born in Southern Ireland, Mr. Powers came to New York in 1909. A friend who preceded him had promised him a job on the New York police force. But, as he told a friend here later, he found the job specifications dictated by the Tammany Hall bosses involved dealings in which he preferred not to participate.
He came to Rochester in 191U and attracted the attention of Mr. Eastman, who gave him a job tending the gardens and patrolling his East Avenue estate. He worked on the Eastman estate until 1924 when he became gardner at the Rock Beach summer home of William G. Stuber, then vice president and now honorary chairman of the board of the Eastman Kodak Company. In 1928 he went to work in the roll film coating department at Kodak Park and stayed on there until illness forced his retirement in 1947.
His wife, Carrie, died in 1941. They were married here in 1918. Before his illness, Mr. Powers had lived in Meigs Street. He was a 25-year member of the Kodak Pioneer Club. Friends here said there are no known relatives living in this country. The body was removed to the Frcars Funeral Home, 1340 Lake Ave., where services will be conducted later this week. Burial will be in Riverside Cemetery.
https://www.newspapers.com/newspage/135420977/If the theory is right, then in 1929 Mary (Walsh) Power said she was a widow so she could remarry, since there are no grounds for divorce in the Catholic church. She was free to marry since her husband Patrick had re-marrled. Or maybe she had him declared dead if she had not heard from him for whatever time it took legally.