As for the clothes, with every historical dress, you have to start at the foundation. No dress will fit and look as it "just dropped through a split in the fabric of time" if one does not wear the proper underclothes, so let's just start at the bottom. Regency clothes look like there is not much underneath, but that is just an illusion. the first layer is... yes, they did wear some kind of corsets- a pair of stays mostly to push the boobs up high, but that is not the first layer. No woman in their right mind wears stays or corsets directly on their skin, there is a shift, a chemies, or something similar underneath.
Also since I have a considerable extra weight, my thights are chafing in the heat, I need drawers as well.
Learned my lesson last summer in Savaria, for a two day even you need at least two sets of underwear.
Drawstring neckline, tiny pintucks and lace at the edges.
Actually only the two legs were put up on a waistband, I cheated just a little bit, by adding a normal waist.
They were narrower and longer than their victorian counterparts, sometimes even to the point where they were peeping out from the hems of the skirts.
I tried to emphasize the narrower, but longer lines with vertical pintucks and added ruffles as a nod to sauciness.
The next time: corset.