Domain Zoo is extremely low to the ground with Wild Nacatl, Ragavan, and burn like Tribal Flames and Lightning Bolt, so we want cheap interaction. Consign to Memory costs one mana and has narrow but real targets: it counters Scion of Draco, which is a colorless spell, and it counters triggered abilities such as Ragavan's damage trigger, Territorial Kavu's attack trigger, or Leyline Binding's exile trigger. It can't hit their colored spells, including their own Consign to Memory, so two copies is plenty. March of Otherworldly Light is instant-speed exile that is best used on the cheap threats: X=1 exiles Ragavan or Wild Nacatl for two mana, and X=2 handles Territorial Kavu. Don't plan on it for Leyline Binding (mana value 6) or Scion of Draco (mana value 12), which cost far too much. Fatal Push stays in. Ragavan, Wild Nacatl, and Territorial Kavu (mana value 2) all die to it without revolt, so only Scion of Draco and Quantum Riddler are out of range. Faithful Mending is too slow against this aggressive curve, since we only gain 2 life while burn is pointed at our face. Prioritize Solitude and Prismatic Ending to answer their efficient threats before they snowball.