Considering the stakes of the Huge, the government has made the environment rather very hospitable for the schools that the Lilies reside in as thanks to their work. Also the world views them as heroes, constantly thanking them for their service and even offering them free stuff in exchange. Additionally, some Lilies willingly enroll just so they can be like their heroes, which was the case for Riri.
As harsh as Yuyu may seem, once she finds out Riri's birthday is soon, she actively goes out of her way to ask anyone associated with Riri on what she might like. Riri herself seems a bit sad that Yuyu isn't there for her day, but Riri really appreciates Yuyu trying to go out to find her something (which ended up being ramune), to where she and Yuyu end up hugging afterwards.
Episode 10 shows how many students care for Riri even after she got punished for her actions.
Yuyu was determined to find Riri's lost four-leaf clover. She and the rest of the legion got together to team up and try to focus on finding it. They even combined their skills (at least viable ones) together so they could be resourceful.
Kaede wanted to help Riri as well. She had found the original clover early on washed up in the shore, but it was destroyed and shriveled. With some assistance from Shiori, she had made a decoy clover and placed the real clover in the shore (which was found later). While she was worried she was going to get shunned for it, everyone still found it heartwarming that she'd do something like that.
On the last day before Riri was free, everyone from the academy decides to help Yuyu find the "clover". With all of their combined powers, they manage to find the clover.
