Here we have the leaders of the Northside Gang: Dion O'Banion, Chicago's favorite florist (with characteristic flower in his lapel), and his successor, Hymie (the Polack) Weiss. How come you didn't include George (Bugs) Moran?
Your source for the Belcastro photo is wrong in identifying him as Klondike O'Donnell. Go to this source and you will see Klondike as the first photo alongside "Gang Leaders":

http://www.mistercapone.com/people.htm


Ntra la porta tua lu sangu � sparsu,
E nun me mporta si ce muoru accisu...
E s'iddu muoru e vaju mparadisu
Si nun ce truovo a ttia, mancu ce trasu.