Just so you know, Hellions also have (nearly) blank faceplate helmets, and they don't have the sticky out section at the back like the reavers. I say 'nearly' because they actually do have abstract eyes/scars cut into them, but it would probably be easy enough to fill them and smooth them off. If not, you can always get very similar, properly blank, helmets through Shapeways:
https://www.shapeways.com/product/GHK6SB5AS/dark-eldar-space-elf-reaver-helm-x10?optionId=65695795&li=marketplace (have a look around on there, there may be other similar heads). You can actually get prints in what they call high quality plastic, which is actually somewhat transparent. Don't know if that would somehow aid in the effect? Maybe painting fire effects with translucent paints, then gloss over the top to give greater impression of depth? It would be interesting to see if that works, anyway.
In terms of bodies, it looks like Drukhari are closer than Craftworlds, simply because of the Drukhari wearing what's more like bodysuits (Wyches look closest to me) and Eldar have much more sculpted armour that might not be appropriate for the look. It would be cool to see that glass/fire effect on the exposed skin of a Wych torso - in fact you might've inspired me to copy your idea at some point in the future! You'll likely have to remove all the spikes and bones and such the Drukhari are festooned with, though.
I played Endless Space 1, didn't know about 2, but I'm now considering buying it just because of those cool looking Vodyani.
Edit: Oh! Also, don't forget the Eldar Spiritseer has a blank faceplate helmet.
Edit 2: It's called 'fine detail plastic' through Shapeways.