The petticoat is a frankenstyled reproduction Victorian steel boned bustle pattern. The historical version of the dress this petticoat is designed to be worn with would be floor length and a bit more columnar in shape when viewed from the front; I shortened it and added extra ruffling on around the bottom half.
The costume is two pieces, dress and overskirt. The overskirt drape and polonaise are attached to the brown waistband and wrap around. I draped and redraped that overskirt so many times; I generally draft patterns flat and geometrically so getting this how I wanted it to look, length, width, and pleat-wise, took some work. The polonaise/back bustle thing is shaped with batting to create the smooth, Disney-ish shape (though obviously I did pleat it; darts looked weird).
The scallop trim is attached to the lining. In a minor miracle, the hem circumference ended up being perfect for my scallop width and they met right at the center back seam. As all scallops are these were a bit obnoxious, but for the first time ever I pressed them using a stiff template (same template I used to trace the seam line). I don't know why this never occurred to me before. It's faster and less tedious than pressing with a point turner.