Mono Red Madness wants to race, so Healer of the Glade's 3 life on entry each copy buys crucial turns against Fireblast and Lightning Bolt math. Mesmeric Fiend can strip a key piece like Fiery Temper or Kessig Flamebreather before it can snowball damage. Dread Return is clunky against a fast clock and Masked Vandal has no real artifact/enchantment targets here, so both can be trimmed. Graveyard hate like Faerie Macabre is not needed since the deck's discard is madness-based exile, not graveyard recursion (except Sneaky Snacker, which isn't worth dedicating slots to answer).

Dimir Control grinds with card advantage and removal, so Mesmeric Fiend proactively strips a Counterspell, Snuff Out, or Cast Down before it can be deployed. Faerie Macabre's discard ability lets you exile the flashback half of Plunder the Trollshaws from their graveyard, and it's a black body that dodges Snuff Out when played proactively. Lotus Petal and Quirion Ranger are lower-impact speed pieces that matter less in a grindy matchup where card quality beats speed. Keep the core mill/reanimation engine intact, but play around Counterspell and Spellstutter Sprite, which can stop Balustrade Spy or Dread Return (Dispel can't, since neither is an instant).

This is the mirror, so the race is about who mills and reanimates faster while disrupting the other's graveyard plan. Faerie Macabre's discard ability can exile key reanimation targets (their Generous Ent, Troll of Khazad-dum, or a milled Balustrade Spy) right out of their graveyard, directly slowing their Dread Return plan. The extra Masked Vandal gives you another body to exile an artifact like a stray Lotus Petal if needed, though its main value here is just as a creature. Lotus Petal and one Gatecreeper Vine are cut since mirror matches reward disruption and bodies over incremental mana/land tutoring.