Even though I have passed to the next round of RAW I have decided to send these materials. VR experience has turned my life upside down and I hope that this information will be useful for someone.
Sketching an idea in Quill
Then when the setting is figured out more or less I start using Oculus Medium (this is more of a toy rather than a real professional instrument, but it is GREAT for making a prototype.
After doing all this I export the model as an obj. file and go to Zbrush for polypainting. For some reason Zbrush doesn't distinguish between different layers created in Medium: aliens' eyes are created on a different layer, but however not displayed as a separate subtool. From Zbrush it goes to Keyshot for render and there the eyes are already displayed as a separate object.
This is what the render looks like straight from Keyshot:
There are some flaws, but I don't pay that much attention to them because I'm gonna fix that manually in Photoshop in the post-production.
And Voi-la! 15 minutes more and my illustration is here. It needs a lot more to be done to be ready to go, but hey... that's a good base. I tried to keep the entire modeling time under 2 hours + 15 minutes extra for post production.