I can at least confirm the ladder two in the first point. If you don't get the intended route, don't save and soft reset and start your file without starting the C-gear. Soft reset as many times as needed.

I have yet to get through Pokemon B2/W2 so I'll confirm those when I get to those games x_x

Suppose I'm something of a Shinpachi myself youtu.be/_aTaSZiCuRg