For the women, I actually went a little bit earlier, choosing more medieval style gowns. Corsets are overused in fiction of this style, and I was feeling bugged by them, so I stayed away. Gowns with lots of petticoats to make them flare at the skirt, then tight through the waist and bust, often with ornate sleeves. Not full blown, overdone renaissance sleeves mind you.
Actually, to be honest, I mashed modern prom dresses with medieval dresses, and came up with a hybrid in my mind. A couple of modern gowns I used as a reference:
That Kelsier looks pretty good, though as I said, Kelsier didn't often go with the full suit--he was more casual than many. Breeze always has on his full vest and coat, but Kelsier would often do without either. In the early chapter where he meets Dox on the wall, however, he would have dressed like that. Personally, I also envision him with hair curling down rather than going back, but that's a matter of personal imagery, and I don't know that I talked about it much in the text.