Disdainful Stroke answers their top-end bombs like Deadly Cover-Up, Together as One, and Unholy Annex // Ritual Chamber's back half, all mana value 4 or greater. Get Lost is flexible removal that can hit Professor Dellian Fel or Firdoch Core once it's animated, or an enchantment like Unholy Annex if needed, giving us more ways to interact with their sticky permanents. Nurturing Pixie doesn't do much work against a grindy midrange deck full of removal (Requiting Hex, Bitter Triumph) that will just kill it, so we shave one copy. Erode is redundant with the incoming Get Lost and our existing removal suite, so we trim one copy for the more versatile option.