Containment Priest shuts down Green Sun's Zenith and Natural Order completely, exiling the fetched creature instead of letting it enter, which is devastating against their Craterhoof Behemoth and Atraxa, Grand Unifier lines. Lavinia, Azorius Renegade taxes their noncreature spells like Green Sun's Zenith and Natural Order based on land count, and counters any free spells they might bring in. Stifle has few profitable targets against Elves' mostly mana-ability-based engine (which can't be targeted), so it comes out; Force of Negation is less necessary here since Elves rarely plays impactful noncreature spells worth countering on their turn beyond the tutors already covered by Containment Priest. Keep Swords to Plowshares and Terminus as our primary sweeper/removal against their creature-heavy board.