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Asking to take Lin's panties, specifically from the white suitcase, will cause the note to spawn in the kitchen. This is one of the things that must be done in the loop you are trying to alter the note.
Once you've got the note (and it sounds like you do have it), you can do the rounds of talking to people about it, as well as using it as an excuse to open the suitcase. This will require solving the riddle... but talking to the various girls about the note will give hints (except Haily, who will immediately solve it). This will probably take the rest of the run, but only has to be done once and the game will remember permanently.
This is why these things stay crossed out, because it requires them to be done once ever. This is contrasted with the things that have to be done specifically in that loop. So talking to Lin has to be done, as it spawns the note in the kitchen. Similarly playing with Lina's camera on saturday. Once the conditions have been met, talking to Jenny and Lina in the garden will also allow the various Lina interactions, including one to alter the note.