Kanaan, who won Honda's second start at Phoenix, parlayed pace and consistency into the point lead for most of 2003 before being eliminated from the title chase in the season finale and winding up fourth in the standings.
Franchitti, who missed all but three races last year due to a back injury from a freak motorcycle accident, returns with a clean bill of health and a new sense of purpose as he begins his seventh season with his current team.
Herta got the call from Michael Andretti to replace Franchitti in late June and immediately put his good friend's team in victory lane at Kansas City in only his second IRL start.
Wheldon put together five top-five finishes, including his first podium (third in the Texas finale), to take Rookie of the Year honors and earn another tour of duty with AGR.
"It's a great group of guys and we've got four good shots at winning any race," said Kanaan, the personable Brazilian who was married one evening last autumn and racing go-karts the next day. "This team has a lot of talent and a lot of expectations.
"I'm really glad Dario is back because we're great friends and he's really good at setting up the car."
Added Franchitti: "This is more like a family than a team and nobody has any secrets...we all work together." Team Rahal is back for its second run through the IRL as Buddy Rice has assumed Kenny Brack's seat while the 1999 Indy winner recovers from serious injuries sustained in the '03 finale.
"Nobody ever wants to get a ride over somebody else's misfortune but I intend to make the most of this situation and get some good results while Kenny is healing," said Rice, the 2000 Formula Atlantic champion who nearly won his IRL debut in 2002 and ran 13 races for Team Cheever last year.
Brack suffered a broken back, sternum, right leg and fractured both ankles in a ghastly accident at Texas but the veteran from Sweden is back home in Columbus, Ohio doing six hours of therapy a day.
"I don't want to come back until I know I'm ready but I definitely want to race again," said the 1998 IRL champion. Greg Ray returns as the IRL's lone owner/driver with Access Motorsports and the 1999 IRL champion's 2003 highlight was running strong all day at Indy for an eighth-place finish on the lead lap.
Rookie Kosuke Matsuura moves into the Super Aguri Fernandez ride previously driven by Roger Yasukawa after coming off some impressive runs in the German Formula 3 and Formula Renault V6 series. Yasukawa has a 2003 deal to run Motegi and Indy with Team Rahal.
"With all four of our teams returning, an expanded seven-driver lineup, and a year's experience in the IndyCar Series, 2004 is shaping up to be an exciting year for Honda in the IRL," said Robert Clarke, VicePresident and General Manager of Honda Performance Development. "We're looking forward to the start of the season at Homestead-Miami Speedway, February 29."