Song was the highest-ranked player at Queenstown in 2017, on the back of his victory over Jordan Speith in the Singapore Open.
He remains inside the world's best 100, earning around $1 million in 2017, finishing 11th on the Japan Tour moneylist and 19th on the Asian Tour.
Their entries are the result of the New Zealand Open's developing relationship with the Asian and Japan tours.
The trio join PGA Tour star KJ Choi, Hendry, Fox and US-based Kiwis Tim Wilkinson and Steven Alker already confirmed for the New Zealand Open.
Tournament director Michael Glading said the field was shaping as the strongest in recent times.
"Both Chan and Steven are outstanding players in brilliant form last year, and they have achieved their rankings without basing themselves in the more lucrative golf markets in the US and Europe," said Glading.
"I'm still working through a number of other approaches and I'm confident 2018 will be the strongest field in our time staging this event."
Kim and Han have similar backgrounds, completing excellent amateur careers in the American collegiate system, although both took time to find their feet in the paid ranks.
Kim, noted as one of the biggest hitters in the game, was impressive in finishing in a tie for 11th at the Open Championship on debut, after earning his start courtesy of his victory in the Mizuno Open in Japan.
Han, a graduate of the University of Nevada, Las Vegas, where he won the prestigious Porter Cup, went into the Web.com Tour out of college but could not settle after playing in Asia, Japan, Canada and China.
Han played in the New Zealand Open in 2005 at the Hills, when it was part of the Web.com Tour.
"I'm very excited to be returning to New Zealand," he said.