When I model figures, I use fondant with tylose powder added to it. (You can read more about using modeling paste and tylose here). One of these days I'm going to have to try my hand at modeling chocolate. I think what's holding me back is that although these figures are edible - you're not really going to eat them, though. Are you?? So, it seems like a waste of good chocolate!
There are a few things I find tricky with realistic figurines - the limbs and eyes being a couple of them. 6 in total, actually!
(Does she look super-wide-eyed to you?!)
This is how I made the skirt for Miss Wide-eyed Ballerina:
Then just a bit of frilling with a toothpick, and it was a perfect fit around her waist.
Now, just to work on the eyes, arms, legs, hands....!