Mono-Green Landfall floods the board with mana dorks and value creatures (Llanowar Elves, Icetill Explorer, Mightform Harmonizer), so Slagstorm is a premium sweeper and Firebending Lesson's kicker mode provides heavy removal against their small-to-medium bodies. Flashfreeze is excellent here since every threat they play is green, letting you counter Bristly Bill or Mightform Harmonizer for two mana. Soul-Guide Lantern disrupts their graveyard synergies (like Icetill Explorer) and is simply a cheap artifact to trade for tempo. Cut slower card-selection spells like Stock Up and pure counterspells that don't stop their proactive curve, since you need to be answering bodies, not digging.

Dimir Midrange is stacked with high-value planeswalkers and noncreature spells like Kaito, Bane of Nightmares and Requiting Hex that reward proactive countermagic; Negate stops Requiting Hex, We Say Thee Nay!, or Nowhere to Run cold, while Disdainful Stroke handles four-drops like Enduring Curiosity. Spell Pierce is a cheap tax that punishes their tap-out turns for Nowhere to Run. Trim Broadside Barrage since their creatures are mostly small utility bodies rather than big threats worth a 5-damage removal spell, and cut some cheap Lesson filler for more targeted interaction.

Dimir Excruciator wants to durdle into Doomsday Excruciator and Day of Black Sun, so Soul-Guide Lantern is huge, exiling their graveyard to blank Superior Spider-Man's Mind Swap ability and slowing their Stock Up loops. Negate and Spell Pierce are efficient answers to their Requiting Hex and Bitter Triumph removal, protecting your own threats. Cutting two copies of Great Hall of the Biblioplex trims a slow late-game plan since this matchup rewards proactive pressure and disruption over grinding mana sinks; Broadside Barrage is weak against their mostly small/nonexistent creature base.