I'll focus on hit sounds here.
[Unfortunate Promise]
00:20:662 (1,2,3,4,5) - Alternate the clap sound.
00:40:047 (2) - Add Finish
00:46:508 (1) - Add Finish
00:47:431 (2) - Remove Finish and Clap
00:48:816 (2) - Remove Clap
00:50:201 (4) - Remove clap on last repeater
00:55:739 (1) - remove finish
00:56:201 (2) - add clap
00:56:662 (3) - remove clap
00:57:124 (4) - add clap
00:57:585 (4) - remove clap
01:13:278 (4) - remove finish on both ends. Add one clap at start of slider
01:46:970 (2) - remove finish
02:46:047 (2) - remove finish
Listening to the other difficulties, the hit sounds are pretty dis organized in my sense of using hit sounds.
Instead of trying to mod the difficulties which would have me changing near every sound and/or note, I'm going to try and give you a crash course on a (what i think is a proper) method on how to use hit sounds.
When it comes to the CLAP, I tend to think of it as the metronome for the Osu! player. The easier the difficulty, the higher the clap tick you want so the player can keep on beat.
On harder diffs, the tick can stay the same or you can space it out more since there the more experienced players have a better sense of rhythm and/or there are more soft beats inbetween drumming away.
As for Finishers, I prefer to keep the (hard) finish sounds for the final beat in the time signature. Ex. in a 4/4 time signature, i could put a finish on the 4th beat of 1/4 notes. For 3/4, the 3rd beat of the 1/4 notes. For (soft) finished, the same could be done, or something I like to do---add them on the symbols being used in the drumming or to accentuate a powerful or intense part of the song, like you you on 03:30:816 (1,2,3,4,1,2,3,4) - [Shattered Promise]
For (hard) whistles, I tend to keep them for Kiai time. 1/2 beats, or extra drumming off from the metrical beat of the drums. Ex. Drum solo's. As for (soft) whistles, I keep them for softer intensity songs to replace clap sounds or to indicate a softer section of the song.
That, so far, is the general basics I use hit sounds for. To help the player with the song's BPM, spice up the 4/4 or whatever time signature the song has, and THEN get more complex by adding hit sounds off the time siggy to add your own unique groove/music.
4/4 Time signature
1 and 2 and 3 and 4 and
1 clap 2 clap 3 clap 4 clap
1 clap 2 clap 3 clap clap clap
1 clap 2 clap 3 clap 4 finish
1 clap 2 clap 3 clap clap clap/finish
1 clap clap clap 3 clap clap clap
The more complex you get, the more likely you may make the music TOO noisy with additional sounds.
Hope this helped you with getting a solid hit sound board. My advice would be to copy a difficulty, erase all hit sounds and try what I explained above and see how it sounds compared to your original works. Any trouble understanding anything, feel free to PM me or find me in-game. I used some musical terms there you might have a little trouble wrapping your head around if you've never played any instruments before.
Star none the less, the mapping was done very well.