Bereaved Survivor // Dauntless Avenger

You choose which player or planeswalker the returned creature is attacking. It doesn't have to be attacking the same player or planeswalker Dauntless Avenger is attacking.

Multiple creatures dying will cause Bereaved Survivor to transform only once.

Effects that say that the returned creature can't attack (if the creature has defender, for example) affect only the declaration of attackers. They won't stop the returned creature from entering the battlefield attacking.