Lavinia, Azorius Renegade is a reasonable body here rather than a hard lock. Her tax only stops noncreature spells with mana value above the number of lands they control, so it mostly matters early, for example keeping Goblin Bombardment off the table on one land. Her second ability counters any spell cast without spending mana, which catches a Surgical Extraction paid with life out of their sideboard. Their threats are creatures, so Lavinia does not stop them, but she is a 2/2 that can block and she slows their noncreature plays. Wrath of the Skies can be configured to wipe their wide board of Cat tokens and cheap creatures, since tokens have mana value 0 and most of their creatures cost one or two mana. It also destroys enchantments such as Goblin Bombardment. Celestial Purge exiles a red permanent such as Amped Raptor, Hexing Squelcher, Goblin Bombardment, or the red Warrior tokens from Voice of Victory. Hexing Squelcher has ward, so it costs extra life to target. Their deck has no black cards, so those are the real targets. Force of Negation comes out since their deck is creature-heavy and doesn't present many noncreature spells worth countering on their turn. Stifle stays in, because they have plenty of triggered and activated abilities to hit, including Ocelot Pride's end step trigger, Guide of Souls and Ajani triggers, Amped Raptor's enter trigger, and their fetchlands. A Murktide Regent comes out as the slower threat that makes room for the extra interaction.

Consign to Memory counters colorless spells like Mishra's Bauble and triggered abilities like Orcish Bowmasters' enter trigger or Bilbo, Thief in the Night's attack trigger (note: it can't hit activated abilities, and it can't touch their colored threats directly), and it adds cheap interaction density against this tempo deck. Surgical Extraction can exile Nethergoyf from their graveyard before it escapes, and it also takes any copies out of their hand and library. Terminus is weaker here since their threat count on board at any time is low and a one-time sweeper is less impactful than steady interaction; Force of Negation trims slightly since this is mostly a creature race rather than a combo to disrupt. Keep Swords to Plowshares, Wasteland, and Force of Will at full count as premium answers to their efficient threats and mana denial plan.

Containment Priest is devastating against Show and Tell, exiling anything they try to put onto the battlefield without casting it (Atraxa, Grand Unifier, Emrakul, the Aeons Torn). It does not stop Aluren, though: creatures cast for free with Aluren are still cast, so the Priest won't exile them. Consign to Memory can counter a colorless spell like Lotus Petal, and it can counter triggered abilities such as Acererak the Archlich's enter and attack triggers, Atraxa's enter trigger, or Emrakul's extra-turn cast trigger. Acererak is a black spell, so only its triggers are valid targets. Carpet of Flowers turns their heavy Island count into mana for us. Murktide Regent comes out since it's too slow and gets outclassed by their Atraxa/Emrakul top end, while Swords to Plowshares has few good targets against their combo-control shell; Terminus is dead against a deck with almost no creatures on board before they combo off. Keep Force of Will to counter Show and Tell, Aluren and their other key spells. Keep Stifle for the triggers on Acererak and Atraxa and for their fetchland activations, and to protect our own plan.