Moraug, Fury of Akoum

If the landfall ability resolves during your precombat main phase, the additional combat phase will happen before your regular combat phase. You'll untap creatures you control at the beginning of the additional combat but not at the beginning of your regular combat.

Moraug's first ability checks each turn how many times each creature has attacked. It counts times that creature attacked before Moraug was on the battlefield, and it stops applying if Moraug leaves the battlefield.

A creature that enters the battlefield attacking hasn't attacked that combat. Moraug's ability won't count that combat. Unless that creature has haste, it won't be able to attack in additional combats this turn.