I think we may get carried away by the OP's hope, not expectation, to have the middle seat empty. IMO, that is besides the point.
I will also say that for a short flight, the impact is limited and probably best to chuck this as a water under the bridge situation. It's just not worth it.

To answer the OP's questions:
1. I am guessing some seat swap would have taken place. I can think of various possible choices, but it would be whatever idea the FA comes up with.
2. I agree that flying in and out of countries where this is an issue, the culturally sensitive thing to do is to have some sort of procedure for this. It can' t be the first time it's happened, or the last time.