On the Commission he was close to Carlo Gambino, Tommy Lucchese, Stefano Magaddino until Carlo and Tommy told him to stay away from him, and Angelo Bruno. Bosses he did business with but not sure if he was close enough were Joe Zerilli, Russell Bufalino, Tommy Eboli, Raymond Patriarca Sr, and Santo Trafficante.

He did demote some of Profaci and Magliocco capos, but also split crews. During his reign as boss in no particular order, these are the Capos under him.
John Franzese, Dominick Scialo, Joe Brancato, Salvatore Mineo, Carmine Persico, Salvatore Mussachio, Ambrogio Magliocco, Sebastian Aloi, Vincent Aloi, Enrico Fontana, Nicholas Forlano, John Oddo, Charles Panarella, Greg Scarpa Sr, Nicoline Sorrentino Sr, John Misuraca, Simone Andolino, Vincent Randazzo, Ralph Trupiano, Thomas DiBella,Salvatore Badalamenti, Cosmo D'Amico, Alessandro Debenedetti, Larry Gallo. I know people say Joe Gallo took over the crew when Larry died, but he never gave Joe Colombo the respect and Colombo refused to grant Joe Gallo the rank of Capo, but Gallo did take control of the remaining crew members.

Guys that undermined Colombo or plotted to kill Colombo other than Joey Gallo, were Salvatore D'Ambrosio, Dominick Scialo, Charles LoCicero, John Franzese. D'Ambrosio and LoCicero are the only other members that might have been plotting to kill Colombo.