Okay so there is a reason these were nominated separately.
Hesei and now Reiwa Kamen Rider series exist in softly separate universes, only combined during non-canon crossovers. Kiva in particular is Phase One Heisei where there really weren’t even crossovers, and only two Kiva characters show up in Decade, a different 2 in Zi-O. Of these, the three who were nommed and appeared in outside media are “alternates”. Otoya is an AR counterpart from the Decade-original World of Nega, and Yuri and Jirou have had their histories rewritten when they appear in Zi-O. Any requests from the nominated Kiva pairings refer solely to the versions which appeared in Kiva. Which is, again, it’s own separate universe.
As for Decade and Zi-O… this is complicated because despite both being unique stories, they *are* anniversary seasons, and part of the more-tightly-connected Neo-Hesei era. And Zi-O is very much a soft sequel to Decade. These could probably be changed to KR-AMT or KR-Heisei Era if required. But like. Natsumi and Yuusuke are in no way Zi-O characters. Also it’s just a general rule that due to the standalone nature of the seasons, Toku with separate universes like KR or Sentai be separate even if, say, Power Rangers and Ultraman are kept in one fandom.
Re: Kamen Rider
Hesei and now Reiwa Kamen Rider series exist in softly separate universes, only combined during non-canon crossovers. Kiva in particular is Phase One Heisei where there really weren’t even crossovers, and only two Kiva characters show up in Decade, a different 2 in Zi-O. Of these, the three who were nommed and appeared in outside media are “alternates”. Otoya is an AR counterpart from the Decade-original World of Nega, and Yuri and Jirou have had their histories rewritten when they appear in Zi-O. Any requests from the nominated Kiva pairings refer solely to the versions which appeared in Kiva. Which is, again, it’s own separate universe.
As for Decade and Zi-O… this is complicated because despite both being unique stories, they *are* anniversary seasons, and part of the more-tightly-connected Neo-Hesei era. And Zi-O is very much a soft sequel to Decade. These could probably be changed to KR-AMT or KR-Heisei Era if required. But like. Natsumi and Yuusuke are in no way Zi-O characters. Also it’s just a general rule that due to the standalone nature of the seasons, Toku with separate universes like KR or Sentai be separate even if, say, Power Rangers and Ultraman are kept in one fandom.