So, after picking out 2 dresses in a row that have been discontinued, I finally went to David's Bridal today with FI's cousin (a BM) and had her try on some dresses. We found one that we both really liked and that she was comfortable in and she ordered that.
We picked
this (<--clicky) in Plum. It was more than what I had planned on asking my girls to spend on their dresses, but it's a very nice dress and it will look good on all of them. I am offering to contribute some to the higher cost since FI's cousin and her husband and daughter will all be in the wedding, and my other 2 girls will have to travel up from Florida for the wedding.
Overall, I'm pleased with the dress. Now I just have to drag my Mom to a store and get her to pick something!