IIRC, Kincaid is huge, built like a swimmer and has blond hair. I imagine him looking like the guy who played Thor - but I wouldn't imagine that actor could pull off those "Yassuh"s from BR. Onward goes the search.

As for Gentleman Johnny, he's supposed to be not necessarily good-looking, with a boater's tan, possibly some crow's feet, and he's got those famous green peepers. I don't remember anything about him looking Italian or not

Being from Chicago  Dennis Farina or Joe Mantegna playing  Marcone.