I think that the bandleader pictured above (violinist, centre) is Francesco Maracci, ‘the Venetian virtuoso’ as he was touted in The Oregonian in the early years of the 20th century. Maracci’s Bluebirds was heavily weighted towards woodwinds (saxophones figure prominently in the image).
I don’t know what source led CVA to conclude that the band was called the “Ambassador Orchestra”. I cannot find any Vancouver hotel (or any other institution) in 1924 called “Ambassador” and the band’s name appears (as per normal) on the bass drum. The dominant decorative motif of the room seems to be the humble pine cone (see central light fixture)! So, I think I have identified the band, but as to the location where the image was taken . . . no idea!
(Note: I learned later that there was an Ambassador Hotel in Vancouver, at 773 Seymour (replacing the Hudson Hotel), but that it wasn’t established until about 1939. The Ambassador has since been demolished).