Beginning in July, the original group — minus a discontented Ms. Wretzky — will set out on a 38-date (and growing) summer tour titled “Shiny and Oh So Bright.” And though the shows will coincide with the Pumpkins’ 30th anniversary and exclusively feature songs from their first five essential albums, it’s not all a nostalgia trip. Trying to make this more of a reboot than a reunion, the band has been in the studio with the guru-producer Rick Rubin at work on new songs, which likely will be released as two EPs before year’s end.

“I would say this is the happiest time of the band,” Mr. Corgan said, flanked by Mr. Chamberlin, who was relentlessly positive, and Mr. Iha, who seemed content to go with the flow.

The question now is whether fans — who have weathered years of diminishing returns from Mr. Corgan’s mercurial antics, broken promises and odd decisions — will allow themselves to trust the band enough to care. And assuming they do, how long can this infamously dysfunctional musical family hold it together?

Kevin Weatherly, the program director of the alternative station KROQ in Los Angeles, said that although a reunion may feel less impactful for a band that “never really completely went away,” the Pumpkins’ biggest hits have remained a constant presence, and a set list full of them could likely fill seats with old fans. “You can count the bands on one hand that really defined the ’90s alternative scene,” he said, “and I would put the Pumpkins up there with the biggest from that era.”

At the Four Seasons outside of Malibu, near where the band was finishing recording this month, the three original members were convincingly in sync and professional, if not affectionate. All three are fathers now and in interviews, separately and together, they expressed gratitude for the opportunity to demonstrate newfound maturity and once again tour arenas with their greatest hits.

But with the exception of Mr. Chamberlin, 53, who seems to have fully evolved from a drug-addicted caricature of a rock drummer into a sober Midwestern dad who plays jazz, serves on school boards and does tech consultant work on the side, the Pumpkins remained very much in their classic roles. (In 1996, Mr. Chamberlin was booted from the group for three years after a touring keyboardist died from a heroin overdose after using with him in a hotel room.)