Fatal Push can target any creature, even one with converted mana cost 5 or greater. The creature's converted mana cost is checked only as Fatal Push resolves.

If the mana cost of a creature on the battlefield includes , X is considered to be 0.

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 Murder, or an enchantment you returned to your hand with Leave in the Dust.

Tokens that leave the battlefield will satisfy a revolt ability.

Energy counters aren't permanents. Paying won't satisfy a revolt ability.