Looks like I was worried about nothing. They arrived today (but shipped at midnight last night according to my email...?) and I've already written them all and they're ready to go out with tomorrow's mail!
The dress I ordered last week from Overstock.com came and it's perfect. It fits great and it's going to be awesome for a trash the dress dress. I like that I'll be able to wear this dress with no reservations and go all out and really have a great time. With my real dress (since I want to wear it to our AHR) I would have definitely limited what kinds of fun we would be able to have, and I know FI wants to get completely submerged in the water :P