I like the idea of all different bridesmaid dresses but a cohesive color scheme. Yours would definitely be a little more rustic, soft natural fabrics, and more country in a dusty cornflower blue theme. I think they should all be above knee length.
An oversized button-down shirt monogrammed for each bridesmaid (and white for the bride, of course). Cute and easy for getting ready on the wedding day (especially since you don't want to mess up your hair with a pull-over-the-head shirt!
Go to a thrift store and find the worst bridesmaids dress you can find. Then play paintball for a combined bachelorette and bachelor party.I just like the idea of going out in the worst bridesmaid dress!