1.It isn't about next week Soi Fon will use her bankai or not. But something tell me that she had immediately power up with no reason. If she was that fast a fraccion couldn't be able to follow her step in the first place, at least the battle shouldn't be that long.
2.About the fight between Soi Foi and Barragan, the resalt is clearly that Soi Fon will win no matter what. You guys will see immediately power up technic from Soi Fon again, its value equal with her bankai.
3.That fire ball came from Hinamori 100%