Aura of Silence taxes Phyrexian Dreadnought directly since it is an artifact spell, forcing them to pay {2} more, and its sacrifice ability can destroy a Dreadnought that already resolved. Xantid Swarm's attack trigger shuts off their ability to cast Stifle, Daze, Counterspell, Foil, or any other spell on your turn, letting you push through enchantments or set up Solitary Confinement safely. Keep both Swords to Plowshares in as a one-mana exile answer to their only threat, and keep Solitary Confinement in since its damage prevention stops a Stifled 12/12 trampler cold. Opalescence and Elephant Grass are too slow or irrelevant here and come out to make room.

Azorius Replenish wants to resolve Opalescence and Parallax Wave together off a mass Replenish, so Aura of Silence taxing their enchantment spells by {2} slows the whole plan down, and its sacrifice ability can destroy a resolved Opalescence or Decree of Silence. Tormod's Crypt exiles their graveyard before they can Replenish it back, denying them the reanimation target entirely. Parallax Wave is a liability to keep in mirror-adjacent games against their own Opalescence/Wave plan, so it comes out along with Elephant Grass, which does little here.

Terrageddon wants to Armageddon you back to a bare board, so recovering from mass land destruction matters. Gaea's Blessing shuffles key cards (including itself) back into your library and draws a card, helping you rebuild after an Armageddon or after Wasteland strips your mana. Krosan Reclamation similarly returns cards from your graveyard to your library, letting you reuse lands or enchantments lost to Wasteland or Winter's Grasp. Elephant Grass and Abeyance are less impactful against a land-destruction plan, so they come out.