We know that Jennie has said she has written lyrics for Stay and Solo, as well as said in an interview that "we" (referring to all 4 girls) play a part in creating the songs. I believe there are more songs that the girls contributed to but aren't credited for. I have no idea why they aren't credited but we know YG doesn't like having female idols write or produce their tracks, and maybe there is something in their contract that allows for this to happen without legal issues (since copyright is often brought up in debates regarding whether or not Blackpink writes their songs). I'm not sure exactly but I definitely wonder.
What songs do you think they may have written? I feel like Rosé could've helped compose or write Stay and it's possible that Jisoo, Jennie, or Rosé wrote the Korean lyrics for Kiss and Makeup & Sour Candy.