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In the May 1919 passenger list with Bridget Carroll & Catherine Morrissey, Catherine also has a child Michael J. Morrissey, age 3 with her. 

Considering that and the previous mention of Mrs. Morris Morrissey, I think Catherine's husband was the Maurice Morrissey of the naturalization papers here - https://www.familysearch.org/ark:/61903/3:1:3QS7-99HD-T4KC?view=index&action=view  The Petition for Naturalization said his wife Catherine died in Ireland on 20 Sep. 1919 and his son Michael was born in NY on 25 Apr. 1916. 

Catherine's death record was signed by mother Bridget Carroll.  https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1919/05134/4414041.pdf

Maurice Morrissey, widowed, age 25, sailed from Southampton to NY on 16 Apr. 1920 and the passenger list shows him going to sister-in-law Margaret Long.

Son Michael's marriage license is here, and his mother is listed as Catherine Carroll - https://a860-historicalvitalrecords.nyc.gov/view/11405423

Michael's obituary is here - https://www.newspapers.com/article/the-jersey-journal-obituary-for-michael/145888049/  The New Jersey death index lists him as born 25 Apr. 1916 and died 22 Nov. 1995 in Secaucus, New Jersey.

Margaret's obituary lists her as sister of Mary O'Sullivan.  https://www.newspapers.com/article/daily-news/145855847/

I think your date of birth for Margaret may be off (or Margaret may have had it wrong).  The passenger list you mentioned has markings on it that indicate Margaret sought naturalization in 1940.  The record of detained aliens says she was released to her sister Mrs. Morris Morrissey of 183 West 97th St, New York City, so that might fit with the sister you mentioned. 

The naturalization records indicate that Margaret was born 14 May 1898 in County Cork and was married to James Long on 18 May 1919 in Manhattan and they had 4 children.  The marriage record for that date has parents that fit with your Margaret.  https://a860-historicalvitalrecords.nyc.gov/view/8776138

Gertrude Sarah Wilson b.1872 -d. Date n.k. wife of unknown Clarke.

This looks like it may be Gertrude's marriage record to Drincy D. Clark - https://www.familysearch.org/ark:/61903/1:1:K8F4-KFH  She was a widower and in California. 

Where did the information about Mary's death date come from?  I don't see her on the Illinois death indexes.

The death index is available for free here - https://www.familysearch.org/search/collection/2803479

There is also a Buffalo death index here - https://archive.org/details/buffalodeathindex?sort=title