Although the returned creature is an attacking creature, it was never declared as an attacking creature. This means that abilities that trigger whenever a creature attacks won't trigger when it enters the battlefield attacking.

While resolving Alesha's triggered ability, you can't pay the cost multiple times to return more than one creature card.

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

Any effects that say that the returned creature can't attack (such as that of Propaganda, or if the creature has defender) affect only the declaration of attackers. They won't stop the returned creature from entering the battlefield attacking.

Alesha's triggered ability checks the card's power only in your graveyard. The creature will still be tapped and attacking if its power is greater than 2 after it's on the battlefield.