Hell Realm Sword "200 Yojana in 1 Slash" - This card is really freaking annoying. So yes, you want to take advantage of the slowdown to get through as much of the debris as possible. But the hardest part about this spell card is simply the sheer density of these bullets. Towards the end of the spell this card is atrocious. Really work on reading large gaps as well as small ones, or you might find yourself walled off by all the bullets. Practice, practice, practice. And luck.
Brute Sword "Karmic Punishment of the Idle and Unfocused" - Yes, same basic strategy. You want to get past the bullets before they speed up again and become super hard to dodge. The trick is to know exactly when Youmu speeds up and slows down. During slow down, don't even bother using focus at all. You won't be able to see your hitbox, but it's the only way to get though fast enough. Besides that, just get out of the way when in normal speed.
As for the second nonspell, there's some time after the red/blue bullets shoot at you to move to the side a little bit to redirect the swords. And then the rest is easy. Also, you want to be careful not to be directly under her before she shoots the swords, as that will make your life harder. Aside from that, just be confident in your streaming.