Rosenthal gives Luigi Arditi as the conductor, pp. 171, 808; The Musical World (19 March 1870) announced that the cast would be: Signor Bettini as Guglielmo; M. Faure as Lotario; Signor Gassier as Laerte, Signor Raguer as Giarno, Madame Trebelli-Bettini as Frederico, Madame Volpini as Filina, and Mdlle. Christine Nilsson as Mignon; Kobbé, p. 778, lists the cast as Nilsson, Volpini, Bettini, Faure; Dwight's Journal of Music (2 December 1871) lists the cast as Nilsson, Faure, Bettini, Volpini, and Trebelli-Bettini.
The singer in the role of Philine is listed as: Elisa Volpini in Rosenthal, pp. 171, 847; Mme Volpini in Thomas (1901), pp. IX, 342; and Madame Volpini in Scherer, p. 8. One Madame Volpini was married to a tenor named Volpini (The Musical World, 2 April 1864, p. 213).
The singer in the role of Wilhelm is listed as Signor Bettini in Rosenthal, pp. 171 and 811, and as Bettini in several other sources as noted previously. The tenor Alessandro Bettini was a brother of the tenor Geremia Bettini, who was born in 1820 and died in 1865 (Weinstock gives Geremia's birth and death dates on p. 462; Dwight's Journal of Music, 18 April 1868, p. 13 reveals that Geremia and Alessandro were brothers and were both members of Mapleson's opera company at Her Majesty's Theatre in London in 1863; The Musical World, 2 April 1864, p. 213 mentions that Geremia Bettini and "Signor A. Bettini (husband to Madame Trebelli)" were both counted among the tenors in Mapleson's company in 1864). Although Casaglia 2005, "5 July 1870", lists Geremia [Jémérie] Bettini in the role of Guglielmo Meister, Geremia Bettini died before the date of the Drury Lane performance, so this must be an error.
The singer in the role of Frédéric is listed as: Mme Trebelli-Bettini in Thomas (1901), p. 350; Madame Trebelli in Scherer, p. 8; and Zélia Trebelli in Casaglia 2005, "5 July 1870". Weinstock on p. 305 gives her full name as Zelia Trebelli-Bettini and mentions that she and Alessandro Bettini sang together in Rossini's Stabat Mater on Good Friday 1863. Madame Trebelli-Bettini was married to the tenor Alessandro Bettini (The Musical World, 2 April 1864, p. 213).
The singer in the tenor role of Laerte is listed as Signor Gassier in The Athenaeum (9 July 1870) and as "the late Signor Gassier" in The Athenaeum (27 July 1874). Edouard Gassier (1820–1872) was a baritone (Forbes, Elizabeth. "Gassier, Edouard" in Sadie (1992) 2:358), but the role of Laerte was much reduced in the Drury Lane version (The Athenaeum, 9 July 1870) and could apparently also be sung by a baritone. Casaglia 2005, "5 July 1870", lists Geremia [Jémérie] Bettini as Laerte [assumed to be an error].
The singer in the role of Lothario is listed as: Jean-Baptiste Faure in Rosenthal, pp. 171, 819; M. Faure in Thomas (1901), p. 340; Jean-Baptiste Fauré [sic] in Scherer, p. 8; and as Giovanni Volpini in Casaglia 2005, "5 July 1870", [assumed to be an error]. In addition, the baritone Charles Santley in his memoirs mentions that he had hoped to play Lothario, but the part was given to Faure.
The singer in the role of Jarno (Giarno) is listed as Signor Raquer in the cast announcement by the Italian Opera, Theatre Royal (in The Musical World, 19 March 1870). Although Casaglia 2005, "5 July 1870" assigns Jean-Baptiste Faure to the role of Giarno, Rosenthal, p. 171, Thomas (1901), p. 340, and other sources listed previously assign Faure to the role of Lothario. [Since the two characters, Lothario and Jarno, appear on stage together, the listing at Amadeus Almanac is assumed to be an error.]