Perforating Artist

In a multiplayer game, each opponent in turn order makes their choice once, then all of the actions occur simultaneously. Opponents will know choices made by earlier opponents when making their choices, although a card chosen to be discarded this way isn't revealed until it's discarded.

Raid abilities care only that you attacked with a creature. It doesn't matter how many creatures you attacked with or which player, planeswalker, or battle those creatures attacked.

Raid abilities evaluate the entire turn to see if you attacked with a creature. That creature doesn't have to still be on the battlefield. Similarly, the player, planeswalker, or battle it attacked doesn't have to still be in the game or on the battlefield.