Luhnow and assistant general manager David Stearns met with Lawless, Listach and DeFrancesco in a series of interviews prior to the game against the Mets.
"They're all three strong candidates, they all three have managerial potential and we had good conversations with all of them," Luhnow said. "When it comes to evaluating people internally, the formal interview isn't as valuable because you watch their body of work for years. I've been working with Pat all year, Tony for a couple of years and I've known Tom for a long time. Really just wanted to make sure we included that part of it because there's specific questions I like to ask and I want to hear their answers and compare them to other people."
Luhnow wouldn't put a timetable on how quickly the Astros are going to name a manager, but the process could wrap up as early as next week. Astros executive advisor Nolan Ryan, team president of business operations Reid Ryan and special assistants Craig Biggio and Enos Cabell have been involved in the interview process, but they didn't meet with any of the potential candidates Saturday.
It's also not known if the Astros will make their search public at some point as they've been considering.
"Probably after the season's over I'll be able to be more transparent where we're at and where we're going, but out of respect we're going to allow them to finish the season and focus on that," Luhnow said.
Listach, 47, joined the Astros a year ago from the Dodgers, where he served as the organization's Minor League infield coordinator in 2013. Prior to that, Listach coached on the Major League staffs for the Cubs (2011-12) and Nationals (2009-10) for two years apiece. He also has nine years of Minor League coaching experience in the Cubs system from '00-08.
Listach played in six Major League seasons, which included time with the Brewers (1992-96) and the Astros ('97), and was named the '92 American League Rookie of the Year. He hit .182 in 52 games on the Astros' division-winning team in '97.
"Like I told them, I'm not trying to toot my own horn," said Listach, who's interviewed for managerial positions with the Cubs and Brewers previously. "I've been a player, been a hitting coach, been a coordinator, been a manager in the Minor Leagues and I played the game. There's a lot on the resume that fits in with what they're looking for, and I just hope it matches."
Lawless, 57, has spent the past six seasons in the Astros' organization, starting the year as the infield coach at Double-A Corpus Christi before serving as interim manager at Triple-A Oklahoma City earlier in the year. He has close to 35 years of experience in baseball, including 10 as a Minor League manager.
He took over as interim manager when Bo Porter was dismissed on Sept. 1, and the Astros entered Saturday with an 11-11 record under his watch.
"It went good," he said. "They're going to make a decision and just based on what their information and that's it."
DeFrancesco served as the Astros interim manager for the final 41 games in 2012, going 16-25.
"That was one of the best times in my career," he said. "I hope to get another opportunity to go it again."
DeFrancesco just finished his 20th season as a Minor League manager and fourth with Oklahoma City, which next year becomes the Triple-A affiliate of the Dodgers. He missed the first six weeks of the season while undergoing cancer treatments. Oklahoma City went 74-70 this year and finished in second place in the American North division of the Pacific Coast League.
Last season, DeFrancesco guided the RedHawks to a Pacific Coast League-leading 82-62 record and an American Southern Division title.
The Pittsburgh Tribune Review reported Saturday that Banister, who grew up in the Houston area and played at the University of Houston, had spoken twice with the Astros, and Luhnow acknowledged the contact with him.