The Ravenite was owned by Armand Rava. When Rava went missing, Dellacroce took over ownership. The Gambino family had a strong presence in Manhattan long before Rava became a capo.
Early members in Manhattan.
Frank Alberti, Stefano, Joe, Albert Armone, Eduardo Aronica, Vincent Aversa, Joe Biondo, John Busso, Bartolo Castellano, Salvatore Chiri, Vincent Corrao, Salvatore Curto, Calogero Deleo, Calogero DiCarlo, Accursio DiMino first faction boss of the Gambino crime family in Manhattan killed in 1922, Rosario Dongarra, Pietro Fria, Olympio Garafola, Nicola Gentile, Giuseppe Gennaro, Leo Grillo, Calogero Grisafi, Dominic Ida, Joe and Antonio LiCalsi, Phil LiCastri, Marco LiMandri, Vincent LoCicero, Ignazio Mannino, Costantino, Gaetano and Salvatore Masotto, Pasquale Matranga, Giosue Meli, Rosario Mezzasalma, Onofrio Modica, Giuseppe Parlapiano, Nick Patti, John and Michael Pecoraro, John, Joseph, and Salvatore Riccobono, John Salica, John Sciasia, Joe Silesi, Anthony Spallino, Joseph Stassi, Pietro Stincone, Gaetano Trupia, and Anthony Vanella.
Some of these members moved to other boroughs, states, or back to Italy, and there were other members who did business or had operations in Manhattan but lived in another borough, Connecticut or New Jersey. Most of Manhattan Gambino faction can be trace to Agrigento region. There are a number of mysterious mobsters during that time. The Capo before Armand Rava was a former member of the Camorra in Manhattan and a good friend to Vito Genovese and Aniello Parretti. The mobster who setup Salvatore D'Aquila had allegedly operated from Manhattan.
As far as Dellacroce being overrated, why would Gambino go out of his way to save him during the fallout after Albert Anastasia and then appoint him as his underboss? I guess only Carlo Gambino can answer that.