This was pretty much the back-up plan. But with an element of trying to seduce in Remilia ("Let's show that smug bitch a thing or two about how we do things in Gensokyo!") and the Oni ("Do you even know what they did to your mountain? Now they're meddling in your caverns, look at them trying to freeze you out!").
>Would either of those plans have worked?
>Remilia would certainly have appreciated the idea of taking Kanako down a peg or two, although it might have taken a little spin doctoring to get her to actually come along. Possibly convincing her that you were following
her lead, and not the other way around. It would have been possible, though.
>The oni would have been rather more unlikely. They know that Utsuho took battle to the surface of her own accord, and was then defeated in direct combat. They wouldn't regard Kanako's actions as aggression against them, no matter how much they were inconvenienced by the result. It was her victory, fair and square.
> Why did Mystia hate/attack us again? Year of Winter, or was it just hunger?
>The Keine of alternate Gensokyo came very close to killing her during the Year of Winter, both directly (some of the fighting got pretty nasty as the year dragged on), and indirectly (through nearly forcing her to starve to death as a consequence). Unlike Rumia, who was simply scared of Keine, and naive enough to be swayed fairly easily, Mystia never ever forgave her for this. However, alternate Keine tended not to leave the bounds of Kanako's domain, so Mystia was normally powerless to act against her. When you accidentally crossed her path, at night, a safe distance from town, it would have seemed almost too good to be true.
>would there have been a difference if we had brought Reimu into the dream world if possible?
>Although she would have grumbled about it, Reimu would have come to help if you'd asked her. However, the limits of Mugetsu's ability to bring others into Maribel's dream would mean Marisa would likely have had to be left behind. Reimu would have been more effective at a few tasks (such as defending Maribel from incoming attacks), but less effective at others (actually dissipating the shadows, which required mostly brute force rather than finesse). Also Mugetsu would probably have been more guarded around her since, as hinted in Marisa and Reimu's earlier dialog, only Reimu had encountered Mugetsu and Gengetsu before. To Mugetsu, Marisa was a stranger, but Reimu was someone who had invaded her home and beaten up both her and her sister for (essentially) no good reason.