I don't remember my wife's undergarments because she didn't wear many...
But I remember my wife's sister's because I helped her get dressed! Basic white bra that was two sizes too big and white underwear. Her attendant had a newborn and was with the baby the entire time (duh!) and didn't have time to help my wife's sister, and everyone was so dramatic and chaotic that my wife's sister asked just me to help because I was calm and stoic about the whole thing. I wasn't stoic on the inside, though!