So, here's my costume study, though I've never done this before. No one else seems to have done one for this costume, so I'll take the liberty! Don't expect any kind of complex jargon, but be prepared for several names such as "thingamajig" and "doohickey."
This is a pretty good shot to start with for an overview. It's basically a thin, loosely netted (my shot at seamstress jargon.) underdress with a corset over it. The underdress has lace sleeves that go on the sides of the arms, and the trim at the neckline is also a lace. Over the dress is worn another thin robe with lacy trim (including pink roses).
First, here's a shot of the material:
It's pretty small, but you can see the floral design of the underdress.
These two shots show where the slit ends; it's actually pretty close to the hip, if not directly on it. It's on her right side. You can also see that the costume is worn with thigh-high stockings.
There are some shots of the neckline's trim. The first image looks as though there's a split down the center, but none of the other images seem to show it, so it could just be how it was positioned in that shot. The second image gives a good glimpse of the floral design of the trim.
This shows the lacy sleeves that go directly across the upper arm.
This doesn't look like a difficult corset. I've seen a couple patterns that look like it would work perfectly with it; it's pretty standard for the time, so just about any Victorian corset pattern will work.
Here's a good shot of front -- and it matches the two pattern I've found that would work for this. Corsetmaking.com has perfect supplies for this; I would assume the spiral steel boning would work perfectly with it, and the prices are really good.
There's no image of the corset's back, so it'll be hard to go wrong -- especially since corsets in that time period were laced, so that's what we'll assume is going on back there. ^_^
Here's a good shot of the corset's material and seams. None of the patterns I found were quite as complex as this, but if I'm feeling particularly meticulous with it, I'll just sew those lines in to make it look like the seams. You'll also see the length of the corset; it starts at the top of the bust (with a curved support, apparently), and goes down to the hips.
This shot shoes clearly the material of the robe. It's another sheer fabric, but it's not as detailed as the underdress material. In most shots, it looks like it's made out of crinkly material.
This shot shows the copious (oooh, big word!) train; it's usually seen trailing behind her, so it's obviously much longer than the skirt.
The lace trim seems to go all around (I'm not sure about the bottom, but around the neck and front it's there). It's double-sided and wide. The lace is lined with small, pink roses.
You can see how the roses are spaced well in this picture -- I'd guess there's one every 1-2 inches, probably somewhere in the middle.
This shot on the chest shows something small catching the light with about the same spacing as the roses, so I think they each have a pearl in the middle.
The front crosses when tied, and it looks like the laces are somewhere between just below the bust to the waistline.
The sleeves are pretty loose, and there's quite a bit of slack around the wrists.
The sleeves are lined with lace as well, and can be seen in these pictures.
The lace on the sleeves appear to also be lined on this little, pink roses.
That's all I have. Sorry for the massive images; I didn't bother to create thumbnail images, so this will take a while to load. As for those corset patterns, here are my ideas:
Butterick 4254, view B or C. B is about the same design, but the bust is more subtle in the costume, so I'll probably use C if I go with this pattern.