So far, so good. I didn't knew you had such vocal range.
The lower and mid notes go really well with the rest of the idea.
I'm not so sure about the higher voice, it gives to the vocal melody a sweeter vibe, but I think (just based on personal taste) that range of notes would be better suited for another synth line, maybe as background to contrast with the rest of the instruments and reinforce the melancholy on this piece.