Not a fan of the organ and the viola panned left in at the beginning. I would center those then automate them back over to the left side if you want them there later in the mix.
Nice job with the acoustic instruments. Good balance of bright to dark, good use of compression imo.
At 30 seconds I think the sidestick and kick both sound weak. Too low in the mix and not detailed enough. Both overpowered by the keyboard panned too heavily in the right speaker. And think its too loud through the whole song.
At 1:30 where everything comes in, I think there's way too much bottom snare. It has a lot of loose wet rattle, but not enough tight bulky pop and punch. I would see if I could put a little bit of that in, without loosing the overall character of the snare, which I think fits the song quite nicely.
In that middle section around 1:56, I think keyboard is still overpowering quite a bit. But the tone is nice and the part is well played. And if you can find a way to move the cymbals out of the way of the vocals I think it would help here. The pitch of the note is clear, but his enunciation gets lost in the cymbal crash.
Keyboard arpeggios at 2:54, still too loud. I guess turn the keys down overall and see where that leaves you. Maybe brighten the vocals just a bit at 2:50? I was wishing they were a little wider too.
If your artist would let you do it, I'd try parallel blending something like a shimmer verb or octave effect on that rhodes. I think it would also benefit from a delay tucked way back in the mix. If that's a virtual instrument, is there a way to hear a little bit more of the attack of the mallet hitting the tines?