I get far more emails than I can reply to, but occasionally I do reply to random emails from people I don't know concerning papers I have written. The main factors that lead to me replying are: (1) I ...

Go ahead and ask. It is extremely uncommon. In many years of teaching I have never had a student ask this. But I wish they would! If by chance I see that a student has very nice notes, I sometimes ...

When he asked "are you going back", he may have been trying to show (to you and to the others) that the reason he didn't mention your name in the plan was because you might not be there anymore. I ...