BR is a black/red graveyard aggro deck similar to Rakdos Delirium, so Dismember answers an early Nethergoyf or Dark Matter Manipulator threatening to block or race you. Nature's Claim has real targets here: Fear of Missing Out and Detective's Phoenix are enchantment creatures, and Mishra's Bauble is an artifact, so it can pick off an early attacker or an artifact (remember it gives them 4 life). Consign to Memory is a low-impact card in this matchup. It only counters triggered abilities and colorless spells, so it can't answer their black or red spells, and Mishra's Bauble and mill triggers aren't worth holding it for. Keep Veil of Summer in: Thoughtseize and Flare of Malice are black spells, so casting Veil draws you a card, and the hexproof from black makes Thoughtseize fizzle when it targets you. Veil also keeps your spells from being countered, though they have no counterspells. Note that it won't stop Flare of Malice (it doesn't target) or Lightning Bolt (red). Prioritize resolving your combo before their Thoughtseize and removal suite (Lightning Bolt, Flare of Malice) disrupts your hand and board.