From what I understand Sexy Dress (Nightclub/fancy restaurant) and Sexy Swimsuit (Beach, Pool, Waterpark)result in appearance changes for some of the girls. (and from personal experience, the girls actually has "unwrap" dialog when she gets the gift if it does.). Do any of the other clothing/accessories for the girls from the clothing store result in appearance changes? Haven't discovered (noticed?) any from cute top/swimsuit.
Edit: FWIW tried quickly giving clothing to all the girls (I think, excluding Emma, whom I don't have available), and got reactions from the following:
Cosplay Outfit: Shiori
Cute Swimsuit: Nobody
Cute Top: Nobody
Fancy Purse: Nobody
Fancy Shoes: Nobody
Nice Scarf: Nobody
Purse: Nobody
Sexy Dress: Samantha, Sasha, Shiori
Sexy Swimsuit: all EXCEPT Lexi & Ayesha, though Alexis, Harmony, Kylie, Lavish, and Minami either declined to accept it or Mike refused to give it (Minami) Presumably meaning it is/will be possible, but my current relationship was too low.
Shoes: Nobody
(Note, Didn't bother with slave collar as I assume all girls have SOME sort of reaction to attempting to give it to them, regardless of whether they can wear it due to the gameplay mechanics involved.)