Is it me, or does Gokaiger limit the number of sixth rangers and extra heroes? There were only 15 sixth rangers because the Gokai phones (both Mobirates and Cellulars have 15 buttons). As for the extra heroes, they're clearly divided into two groups. The rangers, and the ally helpers. I can't help but notice that each of these two groups have five. I swear the purpose of having female Shinken Red and one shot extra heroes (but still very important characters) Deka Swan and Magi Mother. It appears that the purpose of eliminating Ninjaman and Gunmajin was so that they could have five ally helpers (Signalman, Kuro Kishi, Zuban, Rio, Mele). Ninjaman and Gunmajin were indeed ally helpers, Boukenger's files about these types of heroes confirmed them.
This make me not trust Gokaiger's classifications of the heroes simply because extra heroes in a three people team (or four people team in the case of JAKQ) are used as fillers for colors or roles not present in that team, sixth heroes are limited so the numbers on the Gokai Cellular, they wanted to find a way to fit ten people in extras where five is the extra rangers and the other five are the ally helpers. I do agree that all of sixth heroes are indeed the sixth heroes of their respective teams, but Toei many times counted Kuro Kishi. Deka Master and Wolzard are definitely extra's in their team as they are apart of the team but not apart like Big One. I would say Deka Swan and Magi Mother do fit, even though they're one shot extra heroes (Like how Mask X1 is a one shot sixth hero). Glad they didn't count Deka Bright, and Deka Gold because they're not apart of the main Dekaranger team. But Shinken Red female is definitely not an extra hero. As for the ally helpers (with the exception of Kuro Kishi), I agree that they're the ally helpers of their respective teams. I definitely place Big One, Green Sai, Black Bison, Kuwagata Raiger, Kabuto Raiger, Abare Black, Geki Violet, Go-On Green, and Go-On Black as the same category as Deka Master and Wolzard.