According to All Wheel Sports Facebook page, the 3 BMX bikers are back from last year. Supposedly, all other cast members are new for KD in 2014.
(I believe some of the former 2013 KD cast members are performing in other parks this year. Practice photos from other Cedar Fair parks show 2 or 3 former 2013 KD cast members performing this year at Cedar Point and at Worlds of Fun [new 2014 show for them]). If you look at the 2013 video above, (just look at the still clip, you don't have to start the video), the gymnast guy in blue is performing at Cedar Point this year and the 2 trampoline athletes in the center are at Worlds of Fun for 2014.
The interesting thing for 2014 is that California's Great America is premiering a spin-off show called Aerial Ice. They use ice skaters / aerial artists combined with All Wheel Sports trampoline athletes & gymnasts. They are performing this in one of CGA's indoor theaters. I believe the park has some photos of the show on their Facebook site.
Anyway, expect a 9-10 member cast for KD's 2014 version of the show. All Wheel Sports Facebook page has a short video clip of some of the cast members practicing for the show. There were 3 bikers, one scooter performer, and 3 trampoline performers in the background. There was one person standing on the left bike platform during the whole clip. Not sure if this person was a show manager/crew member or a performer. They just stood there the whole time. If there are more cast members, they were not featured in this video.