If you can find a way to contact Calvary cemetery personnel, they should be able to tell you if Mary, Maggie, and Thomas Kelly are buried in the same plot, plus other info about them, like birth and death dates.
Picture of Calvary Cemetery:
http://www.interment.net/data/us/ny/queens/calvary_cemetery.htmhttp://www.calvarycemeteryqueens.com/49-02 Laurel Hill Boulevard
Woodside, NY 11377
Phone (718) 786-8000
Fax (718) 783-3584
Calvary Cemetery shows no email address, which would have been convenient.
"The Trustees of St. Patrick’s Cathedral owns and operates Calvary, Gate of Heaven, Ascension and Resurrection cemeteries. "
The cemetery has 3 million burials but only 109000 given on findagrave.
https://www.findagrave.com/cemetery/64107/calvary-cemetery"The cemetery is divided into four divisions. First Calvary is often called "Old Calvary" by long-time residents of the area. Second, Third and Fourth are all considered part of "New Calvary."
First Calvary Cemetery : Filled by 1867, located at 49-02 Laurel Hill Blvd. between the Long Island Expressway & Review Ave.
St. Calixtus Division (south side of Greenpoint Ave.)
Second Calvary Cemetery : Located on the west side of 58th St between Queens Blvd & the Brooklyn-Queens Espressway, land acquisition ended in 1888.
St. Agnes Division (south side of Laurel Hill Blvd.)
Third Calvary Cemetery: est. 1879, located on the west side of 58th St, between the LIE & the BQE.
St. Sebastian Division (north side of Laurel Hill Blvd.)
Fourth Calvary Cemetery: est. 1900, located on the west side of 58th St, between the LIE & 55th Ave.
St. Domitilla Division (south side of Second Calvary.)"
Another avenue is to contact the archdiocese, which might have burial records.
https://archny.org/The archdiocese has an archives:
http://archnyarchives.org/http://archnyarchives.org/genealogy/"At this time, cemetery and other death records are still maintained by the individual parish or cemetery."
That last is at the very bottom of the page of info about genealogy.