Ant the combo will now be deterministic. Mill everything, get 4 narcos, dread return Sharuum, get Desecrated Tomb, mill Dread or Guile 20 times, get 20 Bats with Haste thanks to Anger, attack for the win. Unburial Rites is there as a protection measure for the Dread Return, same with Sun Titan
If you add 4x Ancient Tomb and 1x of Mountain and 1x Plain (dual most likely) the rest of the deck is completely free to explore. You could go basically all out on search and counterspells with:
Force of Will
Careful Study (To remove graveyard things from hand)
And even add 4x Fragmentize in the SB which basically deals with most permanent forms of graveyard hate. You can also easily splash anything that is Blue, Red, White and Black, which will also allow you to cast Unburial Rites from hand.
Maybe that will be a new deck and not Four Horseman, but it is a cool new idea anyway. I call it Four Batman!