Since you've changed the bpm of the map, many notes are out of place at the moment. Lower BPM = Less places on the timeline to fit your notes. Since you originally made your map at 150 BPM, you're going to have a lot more notes than you're suppose to. To fix this, simply replace and delete some notes and try to make everything fit.
The basic rule of thumb when it comes to putting notes on the timeline in a 1/4 Snap Divisor is to use the White and Red lines for the main beats and Blue lines for the secondary beats. For example:
00:11:836 (1) - instead of starting the initial spinner at 00:11:834 , start it at 00:11:490. If you listen carefully, that is where the sound initially starts.
I would recommend starting a slider at 00:15:612 and continuing the beat from there. While you're making the slider, delete 00:15:811 (1) since the slider will take over that spot on the timeline.
00:16:036 (2) - should be moved to the white line a bit to the right of the timeline. Again, since you're using 1/4 Snap Divisor, some notes aren't going to snapped where you originally assigned them due to BPM changes and the fact that a 1/4 Snap Divisor has A LOT less timeline points than a 1/16.
When it comes to the blue lines on the timeline, those are mostly used for streams. Since the BPM is lower than the original, the stream will be slower. Try to adjust the notes according to the timeline and everything should be on beat.