[Kantan]
00:55:000 (31,1) - Delete 31. Having a small break before a spinner gives the player more of a chance to react. Extend 1 to 00:56:578 so that it matches the music.
00:57:842 (1,2,3,4,5,6,7,8,9,10) - d k ddk d k kdd would fit really well in notes 1 through 10 above. It gives a strong downbeat note (don) on the start of both bars (the 1 and 6 notes) and gives new patterns on the triplets for players to learn. It also fits structure wise as the reversed triplets lead into what sounds like a new "phase" (vocal pattern changes, leads into a repeat, etc.)
01:02:894 (11,12,13,14,15,16) - I think just doing a simple d k d k d k here might fit this a bit better.
I'd highly consider copy / pasting the repeat section (00:57:842 (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19) - ) to the second repeat (01:07:947 (20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38) - )to keep consistency. You could definitely keep the drum roll at 01:16:789 (38) - as it is though
01:42:052 (1) - Should start at 01:41:894.
01:45:526 (4) - kat fits a bit better here imo.
01:48:052 (8) - same as above.
01:50:578 (12,13,14) - make this k k d to match as a repeat of the previous section.
01:55:000 (19,20) - make this d k.
02:02:263 (31,1) - Delete 31, make 1 start at 02:02:263.
[Futsuu]
00:29:736 - You could safely add a kat here to match the background drums, this isn't too difficult for a Futsuu difficulty.
00:57:210 (1,2,1,2,3,4,5) - this is a pretty long string of 1/2 for a Futsuu difficulty, you should probably consider removing 00:58:789 (4) - to rectify that.
01:00:684 (8,9,10,11) - this pattern would be much better suited to ddkd. It matches the vocals a lot better imo.
01:04:157 (16) - Move to 01:04:000 - as you're following lyrics more in this difficulty. The vocal timing hits on the red tick, not the white.
01:05:421 (19,20) - make this d k and add a don to 01:06:842 -
Same as with the kantan, I suggest you copy the section from 00:57:842 - over to 01:07:947. I still like the slider at the end of the second section though, so you should definitely keep that.
01:39:526 (92) - Move to 01:39:368.
01:40:789 (95) - Move to 01:40:631, add a finisher don at 01:41:105.
01:50:263 (14) - don fits a bit better here in this triplet imo.
01:51:842 (17) - don for consistency (last three bars had k d).
01:58:789 (31,32) - k d for consistency.
02:00:052 (33,34,35,36,37,38,39,40) - this 1/2 section is a bit too long for a futsuu. Can fix this by deleting 36. I'd also recommend (as I did for the kantan) to delete 40 and move the spinner at 02:02:578 (1) - to start at 02:02:263.
[Muzukashii]
This honestly seems more like an Oni to me than a Muzukashii. Tone this down a bit. I'll leave that for you to decide on how to tone it down, but its definitely too hard for a Muzukashii as it is right now.