Sorry for bumping old thread, but I really am wondering about the world mechanism in LB!
In my opinion, the world was created by the main casts, while the other (like Suginami etc) is just a reflection of how the main casts see them. In Refrain, I think Kyousuke mentioned about ripples one after another to create a bigger one. I feel that it's the girls feelings, trying to create a fake world for Riki and Rin.
I just can't help to think that the girls, in their dying state, realized that they have yet accomplished anything or still having a regret on their own. Then Kyousuke kind of made an offer to them, and they probably think "At least I can do something for the two survivors." or if in more selfish way, "I want to leave no regret."
Also, I think the order of the people reaching out to Kyousuke's offer is the same as the order on how they end up joining Little Busters. (That being Komari > Yuiko > Haruka > Kudryavka > Mio)
Or maybe Kyousuke didn't make offer at all. They just came to help on their own.
Now I don't know about the others, especially Sasami and Kanata. If they have no consciousness inside the artificial world, then after Refrain: Sasami will not be in good terms with LB members (not like she's that close to them though) and Kanata still hadn't resolved the matter with their family. Honestly I wished the anime at least have the scene where Kanata waiting for Haruka to wake up beside her bed with a worried face
And about Miyuki, what if she is the real Koshiki Miyuki, not just an artificial being? I mean, if it was a ghost story, she's like a haunting ghost with regrets left. What if ghost Miyuki entered the artificial world on her own and do her part? Kengo said that he wants to stay in the artificial world because he think Riki and Rin can't handle the reality, but what if he's actually just being selfish wanting to delude himself in his successful heroic act of saving Miyuki?
That turned out... pretty long and full of speculation of my own. Sorry if it's kind of OOT in the latter part.