KC,
All of these are great descriptions of what "suiciding" aka ISP, "Intentional Single Pref" are. For the most part, I dont think it is ever a good idea to suicide. There are way too many risks involved in the recruitment process that make it not worth it to me.
Besides, if a chapter invited you back all week, they must see something great in you that perhaps you dont see in yourself, which is a genuinly good thing. Although, on my campus (not sure if this is true everywhere), if you receive a bid from a chapter on bid day, and you gave them a chance and they still werent for you, you would have to wait a calendar year to go through recruitment again.
As for the dress issue: Is it a sundress or a more formal pref dress? I was thinking if it were a casual, cute dress, say like from Forever 21, you could get away with wearing leggings underneath since they are in style
Good luck, keep us posted and have fun at recruitment!