I don't know how far it can continue. The story started with the two being a couple and the protagonist started to narrate the story of how they got together.
No? The color spread of chapter 1 is pretty much just a colored version of Hina taking Ayumu outside to run with her after rejecting her. Obviously not exactly the same because it was drawn separately, but Hina's clothes and actions match perfectly with that
Perhaps, but if Asuka puts up a fight, it might go on for a several more chapters.
Asuka already pretty clearly took her last shot last chapter, and even basically prompted Hina to realize her feelings, so I don't see why she would
The second arc of the story should just be about the main pair discovering that aliens are real
Actually though that'd be so fun