Here are my sketches and pattern layout from my chemise replica. It's pretty basic.
Next layer is this camisole which goes over the chemise but under the corset. Simplicity 5582 works well with a little bit of altering. Simply make the panels and peplum one piece. Her camisole looks like it is trimmed with a very small bit of lace and some kind of stitch, maybe a feather stitch?
Elizabeth's corset is gorgeous, the cross lacing is very tricky to do, I don't have my corset here with me now, but when I do I will try and do a photo illustration of how to do it.