Temporary Lockdown exiles their whole army of cheap threats at once, wiping Ocelot Pride, Guide of Souls, Ajani, Nacatl Pariah, and any Cat tokens with mana value 2 or less. It also exiles my own cheap permanents like Stoneforge Mystic and Phelia, so time it carefully. White Orchid Phantom is a 2/2 flying first-strike body that blocks their small attackers well, and its enter trigger can destroy one of their nonbasic lands. Deafening Silence limits each player to one noncreature spell per turn. That constrains their Swords to Plowshares, Static Prison and Goblin Bombardment, but it also limits my own Brainstorm, Ponder and Force of Will, so it is a narrow inclusion. It does not stop Ocelot Pride, whose end-step trigger only checks whether they gained life that turn. Erode is cut because giving them a free basic land fetch plays into their aggressive curve. Stifle is cut as the clunkier answer here, since it can only trade with a single trigger or fetchland activation at a time.

Dimir Tempo relies on free spells (Daze, Force of Will) and cheap cantrips to protect a fast clock, so Lavinia, Azorius Renegade is a strong bring-in: any spell cast without spending mana is countered, which shuts off their alternative-cost Daze and Force of Will. Consign to Memory answers Orcish Bowmasters and Bilbo, Thief in the Night triggers (and Moonshadow's trigger), and it also counters colorless spells like Mishra's Bauble. Hydroblast and Containment Priest stay in the sideboard. Their list has no red cards, so Hydroblast has no legal targets. Nethergoyf's escape means casting it from the graveyard, so Containment Priest would not exile it, and Priest would only hurt our own Phelia and Pre-War Formalwear effects that put creatures onto the battlefield without casting them. Two Ponder come out as the weakest cards against a fast, disruptive deck, and the two Erode come out because they hand the opponent a basic land, which undercuts the Wasteland pressure we want to apply. Stifle stays in because Bowmasters and Bilbo triggers, Moonshadow's trigger, and their many fetchlands all give it targets. Keep the full Force of Will and Force of Negation package in to protect your own Tamiyo and Stoneforge Mystic plans from their countermagic and discard.

Containment Priest shuts off Show and Tell for creatures such as Atraxa and Acererak (it exiles nontoken creatures that enter without being cast), making it a strong hate card against this combo-midrange deck. It does not stop Aluren, because creatures cast for free with Aluren are still cast, and it does not stop Show and Tell from putting Omniscience onto the battlefield. Lavinia, Azorius Renegade stops them from casting noncreature spells with mana value greater than the number of lands they control, and counters any spell cast without spending mana, including creatures cast for free with Aluren, which slows their Show and Tell/Aluren plan. Deafening Silence restricts each player to one noncreature spell per turn, which cripples their cantrip-heavy draws but limits us as well. Stifle loses some targets here since the deck is less activated-ability dependent, so trim it for these proactive hate pieces.