1. I dont find anything about this old "approval" rules as it is now changed with a more dynamic system. it is clearly stated in the sub-part of "beatmapset" rules
If the drain time of the highest difficulty is...
...lower than 3:30, the lowest difficulty of each included game mode cannot be harder than a Normal. Because osu!mania does not have a difficulty-specific Ranking Criteria yet, an osu!mania beatmapset's Normal difficulty is defined as a difficulty below 2.00 stars. For hybrid beatmapsets that include osu! difficulties, the additional modes’ lowest difficulties cannot be harder than a Hard.
...between 3:30 and 4:15, the lowest difficulty of each included game mode cannot be harder than a Hard.
...between 4:15 and 5:00, the lowest difficulty of each included game mode cannot be harder than an Insane.
...anything higher, the beatmapset is exempt from reasonable spread rules.
this change is as recent as 3 months ago so if you actually not aware, re-read the rules.
2. Which one? the only thing that multi audio files is allowed is Loved section. and thats where all exception on the Ranking Criteria goes.
3. Not sure which one of this part are complaint