You only ever need 1 sacrifice outlet on the board at a time, so you always want at either Carrion Feeder or Viscera Seer. This is to facilitate a turn 3 mind control into a free sacrifice, as you get more mana, you don't always need a 0 mana sacrifice outlet like those 2 and you can instead use the Altar's Reap.
This deck is mostly a control deck, so if you cant steal/sacrifice something, you simply remove it with Lightning Bolt or Perilous Myr. Blightning helps kill your opponent in addition to its discard function since this deck can sometimes have a hard time actually doing 20 damage while also maintaining control of the board.
If you cant steal a creature, you simply create your own to sacrifice and trigger whatever it is you need, which is why Mogg War Marshal is so good, its 2 creatures for 2 mana, and essentially a third since you can sacrifice it before paying its echo cost and still get 2 creatures+whatever benefit you want from sacrificing.
Finally Kuldotha Rebirth gives you even more tokens to help your damage or to sacrifice as you see fit. It works wonders with Chromatic Star as it becomes a 2 mana "make 3 tokens and draw a card" combo. The artifact lands Vault of Whispers and Great Furnace are required for this deck simply because Kuldotha Rebirth is also in it. You can usually spare the mana since this decks' curve tops out at 3 so sacrificing a land for 3 tokens is well worth it.
