The roles eventually went to Winona Ryder, as notorious hitman Richard Kuklinski's partner Deborah, and Chris Evans, as gangster Mr. Freezy.
Vromen tells Wenn, "Maggie got pregnant, but Winona is so perfect for the role because she's so fragile compared to him, so the camaraderie was really working between them. She's a great actress and was hiding for a while, so I think this movie can really bring her back into the spotlight.
"And James Franco was originally supposed to play Mr. Freezy but his father passed away while they were filming Oz: The Great & Powerful, and they pushed the production, so he couldn't make it. Chris saved us and came down and supported the film."
But Franco still insisted on being part of the project: "James felt guilty so he came to do a scene - as an assigned hit."
The director admits he was blindsided by the acting talents of former Friends star David Schwimmer, who he was initially against casting as Josh Rosenthal.
He reveals, "I was averse to casting Schwimmer; I didn't see it at all. I liked him, he was a good theatre actor and I saw him in a play in Chicago and I'm a huge fan of Friends, but, in a Mafia movie, David Schwimmer really didn't work out for me.
"David went back to New York and called a friend of his who is a make-up artist and they created the look for the role with the ponytail and moustache. Then David sent me an audition tape with that look and I thought, 'Ok, I'll take the chance'."