2018-10-05 : As Dispersal resolves, first the next opponent in turn order (or, if it’s an opponent’s turn, that opponent) chooses a nonland permanent they control with the highest mana cost among those permanents, then each other opponent in turn order does the same, knowing the choices made before them. Then all the chosen permanents are returned at the same time. Next, each opponent in the same order chooses a card in hand without revealing it, then the chosen cards are discarded at the same time.

2018-10-05 : If a permanent has {X} in its mana cost, X is considered to be 0.

2018-10-05 : If an opponent controls only lands as Dispersal resolves, that player won’t return any permanent to their hand. They’ll still discard a card.

2018-10-05 : When you surveil, you may put all the cards you look at back on top of your library, you may put all of those cards into your graveyard, or you may put some of those cards on top and the rest of them into your graveyard.

2018-10-05 : You perform the actions stated on a card in sequence. For some spells and abilities, you’ll surveil last. For others, you’ll surveil and then perform other actions.