Right now the game is fully unified (I'm talking about version 0.5.8) into one single route. This update doesn't send you back near the beginning, it's just that if you want to see the outcome of the choice, you need a save right there. That outcome shows up at the same moment it did with Asami in the previous version, basically near the end of day one.
Now, if you don't have a save at that point, you should have one at the moment when Kaoru says "Surprise" (original route), and by continuing from there, if you had chosen someone other than Asami, the game would show you what happens in that case, but you miss the rest, which are obviously completely different scenes that go all the way up to the start of the second day.
Yes.