Nee-chan really enjoys that she can feel like she's doting on a little sister and bullying a little brother at the same time. She's probably the most defined character outside the trio, but for now I guess she'll remain a nameless annoyance to Keisuke that technically fulfills the social obligations of an older sibling.
At first, I thought Uesugi was such a late bloomer that most outfits would cover up everything changed by their transformation but the hair. Now it's obvious that only works in baggy clothes; Uesugi is mostly just small, not underdeveloped. All the clothes we've seen that carried over are loose, but there were probably plenty of others that don't fit anymore.