'Ghostbusters' director Ivan Reitman on new stars: 'I knew ... we were in very good shape when I saw the four of them together'

Forget everything you think you know about the new "Ghostbusters" movie.

For all the scrutiny, hand-wringing and vitriol, you'd think it was about a presidential campaign, not just a kindhearted comedy based on a 32-year-old idea that features four funny women instead of four funny men. But between the Sony hack, a course-shifting death, and an elusive movie star, a few internet trolls were decidedly the least of anyone's worries.

As producer Ivan Reitman puts it: "The movie is the only answer to the question, 'Is the movie good, or not?'"

In the long and twisty development process, the big question internally was never about gender. It was about whether to reboot or pass the torch.

Reitman, who directed the original "Ghostbusters," had been working on a third film, a pure sequel to "Ghostbusters II," which would have focused on the now-grown son of Bill Murray and Sigourney Weaver's characters. The film was greenlit and a script was in the works – which, by the way, featured a mixed-gender cast – but it wasn't going all that smoothly.

Murray wasn't enthusiastic about a sequel in general and demanded that his character be killed off after five minutes. And then Harold Ramis, the beloved co-star and co-writer of the original, died in February 2014 at the age of 69.

"It just broke all of our hearts," Reitman said. "There was no way to do that movie without him and with a reluctant Bill. I decided I would give up the directing and negotiated a deal to make it possible for the studio to continue this thing that we started."

Shortly after, "Bridesmaids" director Paul Feig entered the picture, through then-Sony Pictures chief Amy Pascal, with interest from comedy superstars Melissa McCarthy and Kristen Wiig. Feig brought on Katie Dippold, who wrote "The Heat," to co-write the screenplay, and they were off – holding on for dear life amid the turmoil caused by the breach of Sony's computer system.

Feig added up-and-coming "Saturday Night Live" cast members Leslie Jones and Kate McKinnon to round out the four Ghostbusters.

"When Paul told me the four people who were on it, I was like, 'Oh, he's going for a beast fest.' All of us are comedic beasts," said Jones, whose worries about how the four personalities would mesh in an ensemble were quickly assuaged.

Feig prides himself on his ability to assemble great comedic energies, and Reitman was on board, too, deciding to give Feig space to make the film he wanted.

"I knew very early that we were in very good shape when I saw the four of them together," said Reitman. "There's this remarkable in-step quality that really good improvisers can do with each other. You believe the truth of them having been together forever, even if they haven't."

Reitman had a simple rule: he didn't want this film to be an insult to the first, a spoof, send-up, or silly version.

And it's not. The story is its own creation about the formation of the Ghostbusters, set in the present day where the 1984 Ghostbusters don't exist.

For Wiig, it was "an easy yes." She took comfort in knowing that they also had the support and participation of the original cast, including Murray, Dan Aykroyd (also a producer), Ernie Hudson, and Sigourney Weaver.

"It really felt like we were being blessed in such a way that we were all part of this thing together. It's kind of what the spirit of the movie is," Wiig said.

Ramis also gets a little tribute, which eagle-eyed viewers will surely spot. His family visited the set that day, which Wiig said was an emotional day, and his son, Daniel Ramis, has a bit role, too, at a heavy metal show.

But beyond the cameos, rock star cast, and bona fides of the creative team, "Ghostbusters" has been overshadowed by a passionate group of naysayers – critical of the cast, the trailer, women, and deeply defensive of their childhood favorite.

"Here's the problem with the internet: It's that small, small minority who scream the loudest and the media covers them, but it's not reflective of the vast, vast majority of people," Feig said.

The cast has a similarly removed and bemused view of the hate.

"You just can't give that much credence to somebody who's like "I'm predicting the future about this thing that's not been made,'" McCarthy said.

The stakes are high, but not necessarily superhero level. The film cost around $150 million to make, and Reitman and Aykroyd have plans for some sort of an expanded universe under the Ghost Corps banner. While there are no specific plans – or contracts – for a sequel yet, the story doesn't exactly close the books on the cast, either.

"I've been waiting for this moment," Reitman said. "Let everyone see it, and you decide."