why not take the fire theme and run with it. hairspray the %^&$%%$ out of your hair and make it red!! make it look like flames. then bring the red down onto your forhead, fading into oranges and yellows around your eyes?

you are one of the few people i could imagine being able to pull this off.

I love the make up you have going on with your examples. The 1st one especially. I did a bunch of models with a similar make up for a fashion show once.
I think the flame/fire theme is cool. If you are doing a silver or metallic dress, then do away with traditional flame colors. If you were wearing a gold dress I would stick with the reds and oranges. Instead create a fantasy fire in blues and purples and greens. This will harmonize with your choice of a silver gown plus give a unique twist. You have a beautiful face with nice open lids which will show off make up that that highlights your contours. Glitter is nice in small amounts in strategic places. Full glitter lips are always impressive. Something like black lips with purple glitter. Or blue with silver. Be careful using dark colored glitters, depending on the light it could look like you have dirt on your face.
Make use of that slit in the dress, continue that make up all the way down and show off your legs. You could do some type of art neuvo flames that burn from your eyes down your face and continue down your leg. With accents of glitter to bump up the dazzle factor. The boots are nice, but I would reccomend sandals, or barefoot. The necklace sounds incredible, if you could find some matching thick anklets, and gauntlets, and arm bands, I think the look of the costume would have more balance and authenticity, plus I think feet are sexy, don't forget to paint your toes! Something like a cape, shawl, or wrap, in a liquid mercury appearance, or chiffon-like in blues and purples would add depth and variation in texture, plus gives more fire like flowing movement. Make up around your eyes that is dark and intense even cleopatra like would give a very witchy, mysterious feel. As for hair, don't be afraid to go asymetrical.
Have fun! I love when people get into their costumes and make up! and it obviously looks like you do.