1: This can be complicated but the relevant path you need to reach is asking to borrow Lina's camera in the talking with Jenny scene
2: That note is a puzzle for puzzle people. Given there isn't any substantial content behind it, there aren't helpful solutions to it in the game, like asking Haily and such. But the answer is a nine letter word starting with C
3: The porn date resolution... I believe you have to trigger Alex's shyness around Lin, who you can then talk to about this on sunday morning. This will allow you to invite Lin to the porn date.
3: Alex's breast expansion is triggered by both the milk, and the massage you can get from her moisturizer scene.
4: Telling Lisa it's okay happens when you are talking about how she chose to move away for her career. Similarly if you talk to her about her job, she will mention a certain drug interaction.
5: Apologies, that question mark is a bug. On friday at midnight Jenny is at the lake.