[3] The magician's real name was, as indicated in [1] above, Giocomo Lizardo. Lizardo was known to friends--and the police in a number of cities--as "Jake" Lizardo. After performing with only marginal success as the "Amazingly Great Lizardo", he changed his stage name to "Harry Potter". Lizardo claimed that this name "honoured" both Harry Houdini and America's first magician Richard Potter [Dead Link, see Wikipedia]. Professor Oliver Stein in the monograph discussed in [1] above claims, without citation, that in 1912, just before emigrating to the United Kingdom, Lizardo legally changed his name to Harry Potter. He also claims, without citation, that Giocamo Lizardo was related in some way to the late Emilio Lizardo (aka John Whorfin)[Dead Link, see Wikipedia]  of Yoyodyne Propulsion Systems [Dead Link, see current Link].

[4] Jacob was the youngest child of Francis J. "Frank" Armour, an immigrant who parlayed a push cart (see photograph and caption from the February 3, 1901 Grover's Mill Gazette) first into a major meat-packing company (Amour's Meats) and the into a world-wide financial empire. Unlike Armor and Company and other companies hurt by the meat-packing scandals of 1898 and 1899 [Source] [Dead Link, see WAYBACK MACHINE], Armour 's Meats survived relatively unscathed, albeit with a quick name-change to Bismarck Sausage Company (and, apparently, significant campaign contributions to influential members of Congress). Despite his fianancial success, however, Frank Armour's claims to have invented the "frank" (aka "hot dog") have been ignored by experts in the field. [Source][Dead Link, see WAYBACK MACHINE])
My recent research revealed that Jacob was born in Austria and originally named "Jakob Siegfried Panzer", reflecting, in order, his paternal grandfather's first name, his maternal grandfather's first name, and his father's family name. His father--originally "Franz Josef Panzer" (named after Austria's emperor)--had Americanized his family's names not long after arriving in the United States from Austria in 1881. (Since Frank Armour was, from all accounts, an ardent German nationalist, giving up his German names seems out of character. However, he was perhaps counting on customers confusing his "Armour's Meats" with those sold by the more famous "Armour and Company".)

My recent research also reveals that, as a child, Jacob was referred to as by family members in English as "Little Jake" to distinguish him from his grandfather who had immigrated with the family to America. However, his school-mates' nickname for Jacob was always "Jack" and "Jack" was clearly the nick-name he preferred throughout his life.