Mono-White Aggro has no red or blue spells/permanents and no graveyard-based engine, so Hydroblast, Blue Elemental Blast, and Faerie Macabre all have no legal or productive targets here. This matchup comes down to surviving their wide go-wide token swarm (Battle Screech, Martyr's Soul, Search Party Captain) with Fog effects and life gain long enough for your card draw to take over; the mainboard is already built for exactly this plan. Murmuring Mystic is tempting as a blocker but is too slow and dies easily to their aggressive curve without providing enough impact to justify a cut. No sideboard changes are recommended; the existing Fog/Weather the Storm/draw-spell shell is the correct answer to a creature-based aggro deck like this.