/jp/ - Otaku Culture

So I finished JQV and have some questions.
After Shimaji underwent partial organic evolution near the end, why did he hear Mei's voice? Did he observe the possibility that Mei was there?
Also, the "new humanity" child in the end. Why was she in the "world" where other humans are still alive?
Also why did Natalia need Shimaji to create her paradise rather than her creating it herself? Because she had literally almost no experience with humans so she is unable to observe their possibility? How did she come into Mei and Shimaji's "world" in the first place? I suspect the kumaneko doll had something to do with it but it wasn't expanded upon.