Elsa's Snow Queen Gown: Building The Foundation

This weekend is finally free of obligations, so I can focus on the first stages of my Dragon Con costuming. We will be taking a break from the Lagertha battledress for the time being, dear readers, so that I can begin on building my Elsa gown.
The dress will actually be one piece instead of a separate bodice and skirt, and the bodice detail will be comprised of all the sequins, rhinestones and chunky crystals.

I'm starting with a semi-corseted foundation to keep the smooth lines of her dress and bodice, extending well past my hips; something akin to the corsets from between 1912-1916 or so.
I don't necessarily *need* this kind of thing, but I want that extra bit of smoothing power we all know and love from corsets. Plus, it will help me get into character, ensure my posture stays proper, and possibly keep my back from getting angry with me after being on my feet for hours on end.

Fitting what will become the corset foundation.

I'm utilizing 1940s & 50s couture fitting techniques out of a vintage patterning book. The little horizontal center tuck might look odd now, but it will give me a perfect fit through the bust.

And viola! I have my new customized pattern for the corset. Ignore the uneven bottom hem.
This will be figured out in the final construction when I can better determine what shape/length is best. Most likely the boning will extend from the top edge, to just above the hip joint for ease of sitting, with the garment made like a boned micro mini dress.
This will also double as the pattern for the outer layer, too. I'll simply extend and shape the lines of the above pattern pieces into a long, flared, floor-length gown

 Should I get stuck at any point during this whole Dragon Con costuming process, I have a special weapon, thanks to my friend Jenny Storm:

In an emergency, I'll crack open "Elsa's Anti-Panic Sparkling Power Jellybeans".
As backup, I have the "Grenades of Minty Deliciousness".