00:03:672 (3672|6,3769|5) - I recommend using a jack here for those 2 notes since its the same chord being played in quick succession !
No, since this sound consistency same as 00:48:000 (48000|5,48073|6) 00:49:165 (49165|1,49238|0), also in higher GRAVITY difficulty there's no jack for this sound and if i'm use jack here it will be very hard for this level and going break difficulty gap, so i prefer keep no jack here.
Is there a reason why these notes 00:04:206 (4206|3,4279|2,4351|4,4424|3,4497|5,4570|4) - are LN and the following stairs arent? I think changing those to LN or changing the mentioned notes to rice for consistency might be better
01:00:220 (60220|5,60220|6) - 01:01:402 (61402|0,61402|1) - drum is not present here and doubles would not fit along with the notes after it. Reduce to single or remove it.
01:52:408 (112408|6,112408|4,112408|5,112477|2,112477|0,112547|4,112547|6,112616|0,112616|2,112685|3,112685|6,112685|4) - this is actually really really hard to hit for this difficulty I suggest restructuring the LN coordination aspect of the right hand patterns
01:56:574 (116574|3,116574|2,116574|1,116574|5) - this is a quad so 01:58:797 (118797|3,118797|2,118797|4) - this should also be a quad for same melody !