It doesn't bring the Riku count to five cuz it's meant to be Ansem pretending to be Riku.Recently, and this is dumb, I learned when you counter Data Lexaeus and depower him for a bit, Sora's level 100 power level rises for a split second before returning. I always wondered why Sora has a power level when it never changed unlike Lexaeus. I'm embarrassed I never noticed such a simple thing.
And I recently learned about the alternate cutscenes in KH1. Like if you skip Monstro and comeback after Riku disappears a evil Riku takes his place. So that brings the Riku count to like five? And if you do Coliseum after Hollow Bastion after Maleficent is defeated Hades still has a cutscene, a shorter one, but a cutscene non the less. It makes me appreciate that KH1 accounted for potential skipping worlds cutscenes.