You're right on that, but how about a new OC named Cure Hatred... Cure Hatred who is once known as Cure Happiness before she is betrayed unexpectedly by Cure Deceit... Cure Hatred will serve as an antagonist and a companion of Megumi who will become Predator Wolf again in order to let herself use the power of Anti-Precure weaponry and mechas to fight against the Precure as an independent mysterious mercenary who lost her family... her former traces of her identity and memories as a person due to Cure Deceit's plans to frame her into exile... Megumi will become a super-durable cybernetic supersoldier with powered armour, guns, weaponry and Precure Infinite Stones (Predator Wolf's ultimate power and strength as well as her health indicator... - starts dimming when dying/always bright when completely at full health) as well as a transformation into a mobile suit similar to Gundam... but armed with several hidden Mobile Armours with a modified version of Neo Zeong being the most powerful weapon and the most valued tool of all her strength as the most dangerous enemy the Precure will face in battle...

For the Precures, a lot of them will side with Megumi Aino as she is innocent with Iona, and Hime taking her side and will never respect Cure Deceit's lies while Yuuko, Seiji, and Maria will take the other side along with those who hate Megumi Aino with a passion... Both sides will be erupted in a civil war that plunges the whole world into chaos while Megumi Aino will become stronger as the mysterious PreCure Mecha known as Meguashi Ainaguashi... and later, known as the hero of the Black Knights only known as Miracle-Arsenal Melkinkuro...

There... the true enemy of the PreCure will rise as the ultimate evil known as Master Obliterationtron who will face Megumi Aino/Predator Wolf as the fated battle between the Precure who lives up to her duty as the hero who faces the ultimate evil in the battle of fates with the last enemy being Cure Deceit who will be defeated in a virtual reality video game tournament with Megumi Aino restored back to normal... but with traumatic mental scars and her powers and superhuman abilities permanent with a drastic personality change while standing ready to help deal with any evil threats along with fellow Precure while the false Precure will have a broken reputation for a long time until they will regain the trust of the public as well as their friends and family...

This is what will happen if in the aftermath... Cure Lovely meets a fallen Precure who was betrayed by the others and turned evil as a result with access to high technology and equipment as well as countless military resources...

This was a really cool oneshot! I for one agree with you, I found HapCha's ending to be "controversial" as well!