'Emma's plane is landing at ten this evening - two hours late.' The 'arrangement' was for the plane to land at eight.
If they are still drinking when I get home, I shall be very angry. There is no arrangement there.
2. After hope we often use present tenses with a future meaning:
I hope he arrives soon.
I hope you are cooking dinner this evening.
I hope you have finished your homework by the time I get home.
It's not really a question of why we use a progressive form, but why we use any present tense form with hope (and bet). I have no simple answer to that.