The instrumentation and arrangement is insanely interesting to listen to, as always.
I'm torn on the execution, particularly mix. At points, it can get pretty sibilant. I would have approached things differently. For instance, the shaker volume and percussion transients are as perceptible and sometimes more perceptible/up-front than the rhythm section -- the low brass, bass, and so on.
The violins at 1:41 and organs are louder than the vocal elements in the section at 2:17, as well as the build into our final big section. In terms of transition and the space you have left to work with on the master, I would have added even more dynamic contrast between these sections. I would grow that gap in max dB as the song progresses for a more bombastic conclusion -- allowing for the vocals at the end to REALLY stand apart from those throughout.
If sibilance or boxy breath noise is stopping you from getting those (wonderfully performed!) vocals to sit right in the mix or perhaps making you fear bringing them up front, try rolling off highs or lows to taste, notching lower frequencies down.
Even de-essing in post via RX or another program can help. Getting them into the same sonic range/vibe as the other instruments, respecting microphone/room frequency responses, and approximating the same ensemble feel is paramount to blending live recorded vocals with VSTs.
I have one big problem toward the end of your piece. It isn't the level of the master, as cinematic pieces are often forgiving in this area, and it isn't writing, playing, singing, arrangement, or even sound palette. It's a single source of ultra high treble, the pipe/reed instrument way up there.
I'll try to explain.
In general, the higher something is in pitch, or the more distance there is between it and other elements of a piece, the louder it's going to sound in relation. I don't know what synth is playing 4 octaves + higher than the vocal line if it's not in fact pipes/reeds, but as the only thing in that gap, it's naturally going to sound screaming loud. It has quite a unique sound, one I like, but I would roll off some of the higher frequencies from that synth, and see if it sits better in the mix.
Alternatively, you can turn everything else up in proportion. I assume you are mixing on monitors -- I am listening on monitor headphones. It may be worth checking the mix in multiple environments, if you can't quite hear what I'm talking about, because the spatial aspect of your mix is bang on, but something is happening there in that range.
In short, wonderful composition. I liked it enough that I even experimented with turning the volume up and down, outside of my normal monitoring and reference range to see what happened. The result was, the lower end of your composition came more into perceived balance as I turned volume up, but the high end of that particular synth became almost painfully loud. So I tried it the other way. I ended up turning the song down by half before the pipe synth was more tolerable.
By chance did you mix this song very quietly? I was shocked when, like magic, once I turned it down, everything felt more balanced. The phenomenon must have to do with psychoacoustics and Haas numbers, which I am not as well versed in as I'd like to be.
Please let me know, as I will be very intrigued!