Tangmo,
fun piece! A lot going on here. Sounds modern, yet injected with a good dose of vintage funk. Drums are little busy for my taste, but I understand they do work well with this composition. Good mix.

P.S. Here is a "recycled" & modded suggestion. I took couple of master classes with a jazz singer/teacher a few years back. One of most valuable lesson points she made was to "find your voice". She understood that I am doing music things for fun, as a hobby (not stage) and suggested not to stick to specific tone or vocal character. I was doing it all along, but not consciously. When she put it in "words" it became much more clearer and I try to remember that every time I try to sing something. Now the modded part. If it was me, I would try to sing it anyway, even if it has to be near whisper or even if you do not hit certain notes, just to sketch it out. Maybe you will like it. If not, it could be a good guideline/map for a future vocalist or even with Vocal synth as David above suggested.

Misha.