MTG: Sacrificing a creature, does this work?

Sacrificing is a part of the payment for the activated ability. Think of it like this; if you replaced "Sacrifice a creature" with pay 2 black mana on both cards you couldn't pay 2 black mana and be able to use both activated abilities. You would have to pay 2 black mana for one and 2 black mana for the other. In your case you would have to sacrifice 2 creatures to get both effects. Hope the ogy worked =)