Having them dress in different styles but in the same color family is a great way to keep your wedding party coordinated and make sure everyone feels comfortable and beautiful too. To do this, work with your bridal salon to select the different styles from one manufacturer so the clothes will have the same dye lot, but the different looks you want. Begin your search with a bridal salon near where you live. Describe what you're looking for. Take a photograph if you have one with you, and ask them to help you find it.
Many salons have informals in the store that are short dresses or two-piece dresses.
Ask to see those. But almost all of my guests will be coming from out of town. If that's the case, then the rehearsal dinner will end up feeling more like Reception, Part I, and will end up costing a lot for my fiance's parents. You're not obligated to invite all out of town guests. What you might consider is putting a note in their hotel room telling them how much you're looking forward to seeing them the next day, and if you can include either a city guide, which is often available from you Chamber of Commerce, or a list of nearby restaurants and attractions, you'll help them settle in more easily.