Queen,
If your girls want to schlep a sweater or jacket, fine. My princesses took outfits of different weights.
BTW>>>
as a disclosure, my father owned more than 15 clothing stores, my grandfather manufactured clothing, I both owned 3 clothing stores and a sewing factory in early adulthood, before going to law school.
Since clothing was our parnossah, I am predisposed to young ladies owning and wearing varied wardrobes.
I also believe that one is supposed to wear one’s best to honor Shabbos, and nothing requires you to wear only one outfit per Shabbos. What is fresh and crisp and clean at 6PM on Friday may be limp, wrinkled and even have a whiff of odor by Mincha Shabbos, especially at a Shabbaton with dancing and activity.
I don’t wear the same clothing in the evening that I wear in the office or court during the day. I also don’t wear the same suit or shirt, etc Friday night and Shabbos morning. I put on a fresh laundered and starched shirt and a suit that is not wrinkled. In summer, I also may change to a lighter weight suit before walking back to shul for mincha.
None of this has to be about showing off or competition. Flaunting wealth thru designer logos is gauche, and often the modus operandi of noveau riche or wannabees.