John was the harbor master in Five Fathoms Hole New Brunswick, Canada

I am looking for any information on the siblings and ancestors of both John and Elizabeth McNulty.
Elizabeth is allegedly a descendant of Joachim Murat (Italian b.25 March 1767 La Bastide-Fortuni?re, died France- 13 October 1815 (aged 48) at Castello di Pizzo, Calabria by a firing squad. Murat was one of Napoleon Bonaparte's generals who married Napoleon's youngest sister Caroline Bonaparte (Maria Annunziata Carolina Murat (25 March 1782 ? 18 May 1839.) Joachim and Caroline had several children one was Prince Napoleon Lucien Charles Murat (May 16 1803- 10 April 1878)who married Caroline Georgina Fraser (Charleston, South Carolina, 13 April 1810 ? Paris, 10 February 1879. They had a daughter Princess Caroline Laetitia Murat (Bordentown, New Jersey, 31 December 1832)who is believed to be the mother of Elizabeth (Murat)McNulty. Elizabeth McNulty's father is believed to be John Lewis Garden(1833 ? London, 1892) but is unconfirmed. John Lewis Garden was a wealthy British business man and Caroline Murat's second husband. Family folklore said that Elizabeth Murat was french, and was visiting family when she met and married John McNulty in New Brunswick Canada. I am looking for confirmation that Elizabeth McNulty is indeed the same Elizabeth Murat Garden a descendant of Joachim Murat. If anyone can confirm, or disprove Elizabeth McNulty's lineage I would greatly appreciate it.