Forum:2+ Gravekeeper's Servant and D. Fissure/Macro Cosmos

If I have two or more Gravekeeper's Servants on the field with D. Fissur or Macro Cosmos active, and only one of the two cards that were milled was sent to the graveyard, does my opponent still declare an attack? Can they try to declare another attack by milling again for the same monster? Do they even mill additional cards with multiple Gravekeeper's Servant?

STULF20X6