Caroline Powell and Lenamore. © Mike Bain
All three were in the New Zealand team for both the Olympic Games in 2008 and last year's World Equestrian Games.
Joining them as a definte starter at Badminton is Neil Spratt and Upleadon.
Fellow Kiwis Craig Nicolai (Just Ironic) and Daniel Jocelyn (Special Advocate) could also get a start - they are 18th and 19th respectively on the wait list.
Badminton kicks off on April 21 and runs through to the 25th.
FEI president Princess Haya will attend the event, and will join event host the Duke of Beaufort and Mitsubishi Motors UK Managing Director Lance Bradley in presenting prizes on the final day.
It will be the second time that Princess Haya has been to Badminton.