They want to be beautiful, certainly not as much as you, but still! You also want them to their advantage and above all consistent with your own outfit. So please, give them advice that will help them choose their dress and sell yourself!
For your friends
If you have a theme, a color code, a cut, a favorite fabric, hand made …
You can opt to host unique bridesmaid dresses like they wear in the U.S. It is up to you to exercise diplomacy and tact to convince them!
If you do not want or cannot impose a similar outfit to all your friends, choose an accessory they will wear and make it a gift to them – a hat, bracelet, necklace, shoes, hairstyle ….
For your mother and mother-in-law
Pretty or not, they also fancy being stylish and comfortable in their clothes. If you do not have time to go shopping with them, or they do not want, be in a clear and diplomatic mood and voice your tastes but without imposing anything for fear of difficult to manage and long to clear side effects! Feel free to make a selection of outfits that you and them both like and leave the final decision to them, it is them who will wear it, not you!