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Long shot on Family Search site if you follow the mothers link it shows her Name as "Annae Partland" although I am not saying this correct but looks right and agree with Tickettyboo above

Name   Margaritta Murphy
Birth Date   14 Aug 1863
Event Type   Baptism
Event Date   16 Aug 1863
Event Place   Cootehall, County Roscommon, Ireland

Margaritta Murphy's Parents
Anna Murphy   Mother   F         
Patritii Murphy   Father   M   

https://www.familysearch.org/ark:/61903/1:1:6T36-H95Z?lang=en
https://www.familysearch.org/ark:/61903/1:1:6T36-H95D?lang=en   

Possible brother but pre above marriage date 
Right Church but different MMN

Name   Patrick Lynch
Father's Name   Thomas Lynch
Mother's Name   Honora Hanly
Event Type   Baptism
Event Date   29 Feb 1832
Event Place   St. Michael's, Limerick, County Limerick, Ireland

https://www.familysearch.org/ark:/61903/1:1:XSHB-H1QM?lang=en

and sister

Name   Mary Lynch
Father's Name   Thomas Lynch
Mother's Name   Honora Hanly
Event Type   Baptism
Event Date   3 Jul 1828
Event Place   St. Michael's, Limerick, County Limerick, Ireland

https://www.familysearch.org/ark:/61903/1:1:XSCH-YTX3?lang=en

Odd follow up based on Father and Mother's (MMN) names and Church 
Possible sister 

Name   Margaret Lynch
Father's Name   Thomas Lynch
Mother's Name   Honora Nealon
Event Type   Baptism
Event Date   20 Jan 1836
Event Place   St. Michael's, Limerick, County Limerick, Ireland

https://www.familysearch.org/ark:/61903/1:1:XSC1-NK22?lang=en

Long shot and Not sure if this helps but based on the Limavady connection via James 

Name   John Logan
Spouse's Sex   Unknown
Event Type   Marriage Registration
Event Date   1855
Event Place   Limavady, County Londonderry, Ireland
Page Number   322
Volume Number   9

https://www.familysearch.org/ark:/61903/1:1:FT1D-H6J?lang=en

Very Very weird long shot

There is a tree on Family Search that has a William Stonier but married to Martha with a daughter called Hannah

Birth: 18 April 1826 Wesleya, Congleton, Cheshire, England
Death: 1911 Leek, Staffordshire, England
Christening: 9 May 1830 Biddulph, Stafford, England

Wife:MARTHA 1829 ?
Married c 1850 in Staffordshire

Daughter :HANNAH 1860

Parents: William Stoner and Martha Pierpoint Watts

https://www.familysearch.org/en/tree/pedigree/landscape/2MP9-LKV

Very odd but is there a chance that there are two Williams and their trees have gotten mixed up over time or as this tree shows one is his DoB and the other his Baptism but both listed as Baptism at some point

Apologies in advance if Ive missed read your post or the information on the tree and wasted your time.

Good luck and happy hunting