If a permanent you controlled didn't leave the battlefield before your end step begins, Hidden Stockpile's first ability doesn't trigger at all. The permanent may have left before Hidden Stockpile entered the battlefield, however.

Revolt abilities check only whether a permanent you controlled left the battlefield this turn or not. They don't apply multiple times if more than one permanent you controlled left the battlefield. They don't check whether the permanent that left the battlefield is still in the zone it moved to.

Revolt abilities don't care why the permanent left the battlefield, who caused it to move, or where it moved to. They're equally satisfied by an artifact you sacrificed to pay a cost, a creature you controlled that was destroyed by Cast Down, or an enchantment you returned to your hand with Cyclonic Rift.

Tokens that leave the battlefield will satisfy a revolt ability.