Thank you so much for the help... I've made a few tweaks. Here's what it sounds like now...
I'm not sure exactly what instrument is being referred to... I think I know the section you mean, though. My best guess is the synth-type, "ah" sort of thing, which is actually playing most of the piece. Is it too loud/intrusive there?
Hmm... yeah, kinda clashy. I extended the piano part slightly into this part of the piece, so it (hopefully) sounds like one of the instruments is taking charge.
I tried to increase the bass, but I'm not sure if that helped the problem. I did lower the volume on the piano part at the end, though.
Actually, I'm not sure if that's reverb... thing is, I'm not real experienced with Garageband, so when little red lights popped up next to the volume on all the tracks I just ignored it. Turns out those are bad? So I guess I have to play with that a bit more, hopefully that will fix it. Maybe.
Not having much luck on the humanizing aspect, but I did at least pan them for now. I feel like some notes are louder than others too, and I'll work on fixing that.