Waveskimmer Aven

Exalted bonuses last until end of turn. If an effect creates an additional combat phase during your turn, a creature that attacked alone during the first combat phase will still have its exalted bonuses in that new phase. If a creature attacks alone during the second combat phase, all your exalted abilities will trigger again.

Some effects put creatures onto the battlefield attacking. Since those creatures were never declared as attackers, they’re ignored by exalted abilities. They won’t cause exalted abilities to trigger. If any exalted abilities have already triggered (because exactly one creature was declared as an attacker), those abilities will resolve as normal even though there may now be multiple attackers.

If you attack with multiple creatures, but then all but one are removed from combat, your exalted abilities won’t trigger.