Talking with Skylish about spread between F-M I'd suggest something
K-F-M is pretty good imo both of them increases on a 2x~ objects amount, but I think Muzu could have a little less notes to have a good K-F-M-O:
[Muzukashii]
Suggest to:
00:51:041 (159) - delete according vocals
00:56:374 (188) - ^
01:09:707 (252) - kat and 01:09:874 (253) - delete, would follow piano and doesn't break the spread with fut
01:11:041 (258,259) - 01:12:374 (264,265) - similar
that's what i suggest, wouldn't break any gap and makes something different here :')