As ever, you guys impress me with your knowledge!
Thank you to everyone who responded with info about the mysteries! Especially John Widmann, Jim Saenger, Ed Arp, Luc Rombouts, Erv Mussman, Amy Brandau, Janet Tebbel, Carol Jickling Lens, Dave Hunsberger, and Rick Watson!
(apologies if I missed anyone, there were a lot of responses on this one! :-D)
#23: Gustave Cantelon
#24: Jef van Hoof, Prosper Verheyden, Henry de Coster, William Gorham Rice, Jef Denyn, Cyril Johnston, Staf Nees. The photo was taken 18 August 1931 at the Hotel de Ville/ Stadhuis in Mechelen, Belgium. This photo also appears in the book “Jubileumboek 1922-1972,” and a cropped version was printed in the GCNA Bulletin in 1997.
#25: The gentlemen with Kamiel LeFevere still remain unidentified
#26: Jeff Davis, John Agraz, Ronald Barnes & David Hunsberger, in the playing cabin at UC Berkeley, circa 1984-1990
#27: (standing, L to R) Richard von Grabow, Charles Sukup, Douglas Schenck, Charlene Nunnikoven (?), (seated) Erv Mussman, unidentified
#28-31: We believe are all taken at the Paccard Foundry. #30 Henri ? and Alfred Paccard