I would be wary mixing embers and super small rasboras. Embers are such gluttons, eating fast and anything. The pygmies will have a hard time finding food, with embers in there, and the much smaller much less boisterous rasboras will be hard pressed to fight the embers.
Wouldnt it look better to do a smidge more rasboras and pygmies instead of embers? Or add in a snail
I have the combo (least rasbora, pygmy corydoras) and tbh I am not too happy. I lost a lot of the pygmies, no clue why, no clue when they just stopped showing up, they are mostly static. the tank looks empty. It took the rasboras a month to settle in - so do NOT get discouraged, for four weeks you wont even know they are there but then boom, they are everywhere, not shy, not skittish at all. I love them, they are boisterous, they are not easily startled. But the pygmies were a let down. I have four now and they are more active than they ever been, but I was so disappointed....