personally I'd do a honey gourami or maybe a m/f pair of honey gouramis instead of a dwarf. dwarf gouramis are just so much larger than the other fish, IMO it would just throw off the scaled down look of the tank. plus, I think the colors of the honey gouramis would look better with the colors of the embers.
I'd do some kind of dwarf cory, or if you dont like them maybe pandas?
to my knowledge there are 3 different color morphs: wild color (yellowish brown females, males have brighter yellow highlights on dorsals and red on their body, blue throats when breeding), golden (the red and gold is brighter on males, female are bright yellow with red highlights on eyes and fins), and sunset (I've only ever seen males; they're red with white on their dorsal fins).
the sunset morph males are IMO very easy to find. golden females have become pretty easy to find too in recent years (granted, I live in NYC and have access to a lot of stores). personally, my favorites are the goldens. I've been wanting for a long time to setup a smaller tank showcasing a pair of trio of them.
ETA: a lot of people sell the red morph dwarf gouramis (http://www.tropicalfishfinder.co.uk/dbimages/colisa_lalia_red_neon_1(1).jpg) as honey gouramis. only buy fish labeled Trichogaster chuna, NOT colisa lalia of colisa anything. IME, dwarf gourami males are much harder one females than honeys, make the mistake of mixing a single dwarf male with a honey female in 10g and the honey won't last very long.