You will get the hint for the second one while swimming, the hint for the third one while going around for the campus, both having a 14 days CD from the last petition coded.. You can get the full code looking for Petition in the HTLM (just open it in a txt reading app)
The second allows swimwear to act as regular clothes on campus. The third will either let you make it so no one (including males) can go topless, or everyone (including females) can go topless
Edit: The second is found after spending time in the pool. The third will be found on a hot/sunny day (in Meltember or Springril, if I remember correctly) in the Mall.