All attackers are chosen at once. You can’t attack with Bishop of Rebirth, return a creature card to the battlefield, and then attack with that creature.
29-09-2017
wotc
If the creature returned to the battlefield has any abilities that trigger when creatures attack, those abilities won’t trigger.
29-09-2017
wotc
If the mana cost of a card in your graveyard includes X, X is considered to be 0.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.